Could not load MRxSMB Device Driver

I've been looking this one up, and I have found quite a few references to this same problem.
Unfortunately, there have not been any posted solutions! But I do have a few suggestions based off some documents I have ran across.

First, MRXSMB: "The redirector (Mrxsmb.sys), is a file-system driver that interacts with the lower-level network drivers by means of the TDI interface." This is used by "The Common Internet File System (CIFS) is the standard way that computer users share files acrosscorporate intranets and the Internet."
Now, the Workstation service "The workstation service receives the user request, and passes it to the kernel-mode redirector (mrxsmb)."
And to add to this, RDR is "Rdbss.sys - All kernel-level interactions are encapsulated in this driver. This includes all cache managers, memory managers, and requests for remote file systems so the specified protocol can use the requested server."

So, the Workstation service handles communication requests at a higherOSI model layer, and to communicate lower in OSI, it uses those driver files. They communicate past the TDI logical layer, which is OSI Layer 4 (I think!).

So, this is all deep networking concepts that I really hate!

But, does any of this help with the problem? Not really; just interesting knowledge.

Shoot! Took too long researching my previous answer.
Ok, to continue:

Open the System Information Snap-In (which gets called by running WINMSD). Open Software Environment -> Drivers.
Look and see if the following drivers are Running: mrxsmb.sys, rdbss.sys & mup.sys. These are all the drivers for the redirector service that Workstation service uses to make the CIFS communications.
I think that the first 2 will be Stopped, according to the errors you are seeing. If I understand the startup sequence of Workstation service correctly, these 3 drivers start up, then the service is considered running.
The ones that are not running, I would replace the .SYS files from the XP cd. Boot into Safe Mode first to do that just to be safe. You will have to Extract them from the cd.