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SQL errors one asingle XP machine

In an office with 6 users having no issues with a SQL database, one user is repeatedly getting errors. Al machines are XP, SP3, .net framework up to date.

The user is okay for several searches/queries but after a few times, starts getting SQL error about object reference not set to an instance. The database can be searched by name, customer type etc. The user selects a customer type from a drop down box and after a few successful uses, using any drop down box at all returns the same error.

Ex. Line 256 if dropdownlist2.SelectedIten.value = 0 Then Exit Function

However all others users using the exact same drop down box to select the exact same customer group has no issues. Again, this also works SOMETIMES for the user having issues, then gets kicked out and asked to login again or receives the above error. This one machine is new on the network and worked fine for her yesterday but has been failing repeatedly today.

Any ideas? is there perhaps an update needed to handle these scripts? It's seems machine related not database, as others have no issues with the same search system.

Any other 'local' info can be provided if needed but the database is stored off site and was designed several years ago by a programmer who is no longer in the country.

Judging by the error it seems database related, but judging by the occurrence and isolation to a single machine, it is local.
Updated - 8th Sep 2010

Answers (5)

0 Votes
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Have you tried
Repairing or uninstalling the client software that this person uses to query the Dbase?
8th Sep 2010

Replies

It's a remote database accessed through a browser. I have run into the problem using Firefox but I don't know if its there with IE8. Good point, I'll have to see if it is the same with both browsers.

Thank you!
Oz_Media 9th Sep 2010
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All else apparently equal,
This "new on the network" looks like a place to start.
8th Sep 2010
0 Votes
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Not necesarily sql server that
but it's unlikely to be a straight program error either as it's only one the one box.

I've be looking for os differences, MDAC and such, or may be network topology, extra latency on it's route. After that it wouldnlt be the first time a .net install has gone wrong.

If not that, then we are dowe to weird and wonderful explanations bordering on small blue rigellians playing a practical joke on you.

PS that line of code should test to see if
dropdownlist2.SelectedItem has a value before it tests to see if it's 0

How it could get into that state I can't say from here , but every now and then it is...
8th Sep 2010

Replies

That's what I came up with yesterday, still haven't ruled it out yet. grin
Oz_Media 9th Sep 2010
0 Votes
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Topology?
So, are we talking about web-based clients?

If the client depends on some javascript in a separate file, then flushing the browser cache could be useful.

Do all users have the same browser (and version)?

Does the server have any limited storage space for each user?

Does this system use "inline javascript"? If a user starts playing with a drop-down while a large page is still downloading, he may accidentally initiate a new page request, thus thwarting the download of some needed code (included or referenced further down the page that was first being downloaded)
8th Sep 2010

Replies

So, are we talking about web-based clients?
YES

Do all users have the same browser (and version)?
SAME BROWSER (FF) WILL CHECK VERSIONS (EDITE: yes, all are the same build)

Does the server have any limited storage space for each user?
NOT THAT I AM AWARE OF, I HAVE NO INFORMATION ABOUT THE REMOTE SERVER YET, WORKING ON THAT, LONG STORY.

Does this system use "inline javascript"?
AS ABOVE

Thank you kindly for your prompt reply.
Oz_Media 9th Sep 2010
0 Votes
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UPDATE
okay so it is browser dependent, duh, why didn't I think of that!? Getting rusty having been out of IT for so long now.

IE appears okay after a few tries, FF, after complete removal, reboot, install, reboot is still having the error after a couple of searches .

Here's the stack trace:
Line 263: ' Note: - running thru. SqlAdapter, not SqlCommand, so need 'exec spName' - this is to allow use of optional params
Line 264: '----------------------------------------------------------------------------------------------------------
Line 265: If Dropdownlist2.SelectedItem.Value = 0 Then Exit Function
Line 266: If ddlCategoryFilter.SelectedItem.Value = 0 Then Exit Function
Line 267: ViewAllGridGet = False


Source File: c:\inetpub\wwwroot\XXXXXdatabase\PCustomer.aspx.vb Line: 265

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
XXXXXdatabase.PCustomer.ViewAllGridGet() in c:\inetpub\wwwroot\XXXXXdatabase\PCustomer.aspx.vb:265
LQPdatabase.PCustomer.RankFilterChanged(Object source, EventArgs e) in c:\inetpub\wwwroot\XXXXXdatabase\PCustomer.aspx.vb:998
System.Web.UI.WebControls.ListControl.OnSelectedIndexChanged(EventArgs e) +108
System.Web.UI.WebControls.DropDownList.System.Web.UI.IPostBackDataHandler.RaisePostDataChangedEvent() +26
System.Web.UI.Page.RaiseChangedEvents() +115
System.Web.UI.Page.ProcessRequestMain() +1099


Do you think it has something to do with "Note: - running thru. SqlAdapter, not SqlCommand, so need 'exec spName' - this is to allow use of optional params"


NOTE: XXXXXdatabase simply used to mask database name for this posting
Updated - 9th Sep 2010

Replies

The expression "Dropdownlist2.SelectedItem.Value" is undefined.
It might be created automatically in IE but needs to be created excplicitly in FF. Or it could be a question about different capitalization. So, you need to find out where and how this object is (supposed to be) created.
TobiF 9th Sep 2010
Unfortunately, as it is an old programmer's scripts I don't have access to the hosting server or scripting. I am not the IT manager here but the sales manager of a small company (20 employees) that outsources such tasks. As this only effects one PC, I cannot justify calling in and paying for tech support on the server side.

Other PC's in the office use the same OS, same updates, same browser and have no such issues though. At this time I have to rule out the script itself and look at the single user who is having issues with a new PC.

Again though, thank you very much for adding your thoughts. I bitch and moan at people's personal, off topic opinions a lot on TR but I have always held it's tech support professionals with the highest regard.
Oz_Media 9th Sep 2010
I have 3-4 browsers on my computer...
I prefer Opera. But some sites don't work. (And some refuse to work, but can be fooled into accepting it anyway, one such example is http://www.hsbc.ae/ )
And today I found out that I can login to a Swedish bank in FF, although I get a clash with another banks system for secure login on IE...

So, this user will simply have to accept that for this particular system, he'll need to fire up IE. happy

Actually, I'm a telecom marketing and project consultant, but TR's profile system didn't offer that combination, so that's why I'm masquerading a bit here. (Just like my Opera does for hsbc.ae!)

BTW! You could try disabling all FF add-ons that user has and give it another try. If it works then you'll have to find which add-on is guilty. Could be some popup-blocker, NoScript or whatever...
TobiF 9th Sep 2010
Haven'r played with the plugins and such, it was a fresh FF install so I don't think she added anything but there ae a few defaults too.

I was a BDM for Nortel, Nitsuko (now offered by NEC) over a period of about 11 years too, business telecom is a pretty cool industry, especially in the PBX based VoIP systems and fibre network design/implementation,not so much into the Avaya's and 3-Com wannabe's of the telecom world but the more established and experienced business telecom providers. I have actually just been approached by a former emplyer, who I have worked for under contract twice now (5 years apart) and am thinking of going back again, plenty of tee times and lunches to pass the day and great 6 figure salary with killer staff to spend a day with, just a bunch of good friends really.

Thanks for your ideas, I'll check plugins and addons.
Oz_Media 9th Sep 2010
It will be interesting to see what you find.
TobiF 9th Sep 2010
It may be a problem/hiccup within the user profile?
Maybe...
NexS 9th Sep 2010
Standalones, just accessing a web based server. I understand that there is still a profile or sorts but it is just first name for record tracking, no differentiating 'rights' assigned.

No customer or company data is stored, it's just like a name directory and sales funnel (customer grading) type of database.
Oz_Media 9th Sep 2010
Permissions or anything. Sometimes the Windows profile corrupts things.

Try logging on as a local admin and renaming the user profile(c:\docs&settings\username.OLD, or something) so that they can have a fresh one.

Might be worth a try.
NexS 9th Sep 2010
the Firefox profile - that will do it too. As I had noted this, above:

Haven'r played with the plugins and such, it was a fresh FF install so I don't think she added anything but there ae a few defaults too.

Fresh install won't help if the old profiles aren't removed first (this includes plug-ins, as well as any possible corruption). edit: Rather, you can leave the old one for bookmark and stuff transfer, but start with a new empty profile first.

So, give FF a shot in (FF) safe mode on a new profile and see if the behavior continues.
seanferd 9th Sep 2010
Sorry for the misunderstanding.
Oz_Media 10th Sep 2010
Okay well I hadn't even thought about FF in safe mode, again DUH, I'll get my IT mindset back in shape sooner or later.

Anyhow, I tried it and tested it in Safe Mode, no problems. So I figured I'd try it in normal mode to make sure it was crashing.

As I had removed the .net framework from FF yesterday, did a clean wipe and reinstall, it wanted to update .net again. I let it do so and didn't see a problem again.

So the user has been happily using it, in normal mode without issue, SO FAR, anyway.

Do you think a crappy .net plug-in install would have effected SQL scripts running in FF? It APPEARS to be resolved, again so far but I never think myself lucky until well tested, I've only been let down by that before. 'AHA, it works....hang on, no it doesn't' LOL. We'll see.

Thanks for that, stupid little issue I should have thought of myself, but that's why the great minds are here to help I suppose.

Fingers crossed.
Oz_Media 10th Sep 2010
It can't have been a flaky installation of .Net. Microsoft would never ever release it in that case happy

But, seriously, I guess it's highly possible that some of your code even relies on the .net runtimes. And it just takes one byte that has by accident changed on the HDD to spur funny things...
TobiF 10th Sep 2010
http://voices.washingtonpost.com/securityfix/2009/05/microsoft_update_quietly_insta.html

Maybe that or the intended fix afterward broke something. Perhaps something somewhat unique involving other factors in this particular FF profile. I know I've killed a Mozilla profile before. It didn't involve .NET, but some combination of plug-ins which would not allow me to copy/paste in the browser.

edit: Yeah, I'll keep my fingers crossed as well.
seanferd 10th Sep 2010
Thanks for all of your input.

After running FF in safe mode, it requested installing .net once restarted in normal mode. It reinstalled .net and has been without problems since. I suppose there was a partial or broken install of .net, when it was starting normally, it must have been ignoring the failed install.

Once run in safe mode and then restarted normally, it seemed to realize the .net plug-in had not installed properly/at all.
After allowing it to install the h.net plug-in, all has been fine and she hasn't complained to me about it since.

I have a lot of issues with people's personal opinions here, with respect to politics and world affairs, however I have always stood fast in saying that the technical support here trumps any other place there is, whether paid support or not.

TR's peer support is amongst the best there is and I applaud you all and thank you for your helpful replies.

Cheers to everyone and enjoy your weekend!
Oz_Media 10th Sep 2010
Have a fine weekend, my man.
seanferd 10th Sep 2010
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