problem ftp authenticating in IIS 5

I am having a problem with one of my servers running win2k/IIS5 serving 20+ ftp sites.

Permissions on root folders are set to Everyone – full control, and for subdirectories I have the following:

(mycompanydomain/Domain Admins) – full control (allows me access from internal net)
(mywebserver/usernamehere) – read/write/exe (for user/client access)

In IIS console, I granted operator priveleges for (mydomain/Domain Admins) and for the users as well.

Up until last week, I could login as domain admin from our internal network and get full access, now I get 550 errors. I reset the permissions on the folders and rebooted the server, and still get 550 errors.

Hopefully this is someting simple that I’m overlooking.

Please help! Thanks for any input.