Need advice on printing problem

There is a printing problem in my office’s network that is keep bugging us; We have a D-Link DP101+ print server attached to HP 5100 PCL 6 printer, some of the workstations could not print some print job properly, the printer keeps printing symbols after a few successful print job from that same workstation.
If this happens, we will have to turn off the print server for few seconds then re-attach it to temporary “solve” the problem, this happen on WinXP/2k or Win9x. Any suggestion?