Error loading profile

After the terminal server 2K has been running for several
days it starts giving users an the error message during
their logon attempt that it can't load their profile and
to increase the pagefile size or the registry size.
Detail: Insufficient system resources exist to complete
request. The problem I am having is that it has plenty of
registry and pagefile space to handle the number of users
that access the terminal server. I didn't know if anyone
else had experienced this problem.