Max users running 2000 as server?

What is the max number of users limitation of win2000 netork running win2000 on server (not 2000 server) All other machines are win98se 15 in total. Randomly, machines tend to drop off util someone else logs off. Server is Dual P-III 1ghz 512MB Raid 0 SCSI 2x 18 GB hd’s.
Could it be limeittd user to a single shared folder and not the server as a whole?