XP and Time Sync Problem in AD

Have some clients at a remote site that are reporting
random drops of network share access to mapped drives.

When it occurs the following message is displayed on the
XP workstation:

<DRIVE> is not accessible.
There is a time and/or date difference between the client
and server.

How is the XP boxes getting out of sync in the domain?
We are synced throughout the entire forest, and it seems
only this site is having an issue.

Any ways to work around this?