yea,if your using the embedded print server,you could try to disable and re-enable it at the embedded jet direct menu.if using the EIO slot,you could just swap a different card in,or use the EIO slot instead of the embedded. the reason i mentioned the communication between the formatter and dc controller is because you said that you swapped out the formatter and it did the same thing,so i would think that it would be in the inner communication direction or with the applications/driver,network or maybe a cable.if you can isolate any particular applications,if it was only happening from some,then that can tell you something.

if you can clear the error and just bypass the network with more of a direct connection and try some jobs it can help narrow things down.or maybe bypass the spooler or bypass the os and driver with an dir>>lpt1 dump.probably need a parallel connect there though.