Roaming Profiles and Metaframe 1.8

We are experiencing a problem with roaming Roaming Profiles not loading on the users systems. It does not happen all the time and the systems we use are 95/98/2000. The main error messages we get are —user desktop can not be loaded or cannot locate profile contact your system administrator. Sometime when a user waits about an hour and than tries to log in s/he will be able to get their roaming profile. Any help be wonderful. Ask questions if need be and will get back to you with the answers as soon as I can since I am interning and not at the office everyday.
some information i hope will help.
Using terminal services/metaframe/citrix 1.8
No Novell,
Using Windows NT servers,Service Pack 4
No Active directory,

Robin