NT4 client problem

I have a very strange problem that I cannot figure out and was hoping
that someone else may have at least seen this problem because it makes
no sense at all to me.

I have a PostGreSQL 8.0.1-r1 server on gentoo.
The data is accessed by MSAccess clients using linked tables. After a
good amount of time, one user complains that the data is not working
well. For example, he changes a value in a drop down box and it looks
like it works, but if he opens it and closes it then the old value is
there. He has done a reboot on his machine and that doesn't solve the
problem. The only thing that solves the problem is to reboot the server.
All of the other clients are Windows 2000 and nobody else has this
problem. I even checked the exact problem that he was having on a
Windows 2000 machine and the problem didn't occur. I checked the WinNT
computer right after that and the problem still occurred.

All the clients are using the ODBC driver 8.00.01.01 from Mar-05-2005

Could anyone could shed some light on this?