Home Directories

The problem at school (where I started to work a project) is that students can’t access their home directory from each workstation. e.g. They are changing classroom and many students can’t access their home directory. They can logon but to access their home direcotory they can’t. This is happening only on workstations, which are running Windows 2000 Prof. Other workstations are running NT Workstation, Win 95/98 and students don’t have problem with accessing home directorie.
The server is running NT 4.o Server. I think the problem could be related to Win 2000 Prof but I don’t know what to do.

It would be appreciated if somebody could help me.
Thank you.