4250N Laserjet 49.FF04 Error

This is a 4250N Printer, The firmware upgrade was done by download, we replaced the Formatter and Memory. I unplugged the printer from the network and they do not get the error. We are using a Novell network with Cisco switchs, any suggestions on what I could check on the network, This is only happening with the 4250N printers, we also use 5si, 8000, 8250, 4000, 4100, &5500 printers.