Cannot access shared folders using \\server\share

I cannot access shared folders or drives on our Windows 2000 Server from any remote location by typing in “\\<servername>\<share>” from the command line (or from My Computer or IE). When “\\<servername>\<share>” is typed in, windows will prompt for a login and password. If an incorrect login or password is entered, it will re-prompt for both. If the correct login and password are entered, it will give the error “an unexpected network error occurred”

I have checked the shared folder's permissions and can't see anything out of the ordinary
The server is Running W2K Server w/sp4 and all computers trying to access it are running W2k Pro w/sp

What does work: I can access two web directories that are located on the server using FrontPage extentions, and I can also login to the server using terminal services

Any help would be appreciated.