Server busy, Please retry

Using WinNT 4.0 Service Pack 5. Ten workstations and one server. Using DHCP for IP addressing. If I reboot a workstation I will have a 50 50 chance that I will get a message box which reads: “Server Busy, Please Retry” and a box to the right end of the message box with the number 4 inside. If I click the press the retry button I will not get the box again and the workstation will log onto the network. It does not make any difference if there are any other workstations logged on or not. Isthere a time value I can change at the workstation or at the server which will allow more tries than before giving up.