Shared network device disconnects ...

I have a single Win2k3 server running as a DC with XP Pro
clients. I have seen several vairants of this issue but
not sure that I have the same thing going on.

After logging in to the domain the users will be able to
access shared resources on the server, shared drives or
even administrative shares, and they will be able to
access shared printers on each others PCs. After about 15
minutes the connections seem to time out or disconnect.
If I try to reconnect to the server, I get prompted for
authentication with an error similar to 'You need to login
with proper credentials, the account you are currently
logged in with has been tried and denied access' even
though 15 mintues ago it worked. With the printers on the
other PCs you wont see anything, just that you cant print
anymore.

I have tried the Autodisconnect reg hack so far with no
real results. Any other suggestions?


Garrett McAlister