Have you added any new scripts on the server lately?
Check to see if there's any file called net.bat or net.cmd in the netlogon share of your PDC.
There can be a rare possiblity that when you use the NET USE command in the logon script, the Net.bat file in the Netlogon share is run instead of Net.exe file in the %SystemRoot%\System32 folder on client machine. As a result, the script can go into a continous loop, and hit the system with multiple mappings for the same share like a boomerang.
If you find such a file, either rename it or remove it and see its effect.
That's the only thing I can think of right now.
I know it's unlikely, but it's possible.
Mubashir
muhammad.mubashir@sbp.org.pk
A mother doesn't spy. A mother pays attention.