User connections limit to a file server?

Our network has been all NT until recently, we upgraded a file share server to 2000 Professional. Occasionally we would get this error on a client workstation:
“No more connections can be made to this remote compouter at this time because there arealready as many connections as the computer can accept”.
Now today, everybody is getting this message. When 2000Pro was installed it was installed with all the default settings. This is our first foray into the 2000 world, what did we miss or do wrong? What do I have to do to fix this so everyone has access?