Lexmark printers going crazy!!!

My employer has several different Lexmark printers on our office
network (Optra T612, Optra T616, Optra S 1855, etc.), accessed by
users via TCP/IP port. A few weeks ago during the Blaster worm
outbreak (coincidence?) we started receiving strange errors on all of
the Lexmark printers, all within a few minutes of each other. The
most frequent error message displayed was "976:2 Srv Net SW" although
there may have been slight variations. Our printer tech has upgraded
the firmware on most of the printers, which seems to have eliminated
the problem. But I'm curious to know what started this problem in the
first place.

Any ideas?