I can try to help

First some more info....
1) What printers are printing to? (i.e. Lexmark Optra T616?)
2) How to you have them setup in the manager? (i.e. print straight to a an IP address, locally connected, or to a hostname, raw, etc)
3) What version of the drivers are you using on the client?
One possible guess of the problem before I see your answers:
I had setup three Lexmark Optra T610's with an Ethernet interface on the network and printed to them fine...from some apps. From others, I would get raw postscript. In my case, the simple solution was to tell the driver on the client to send postscript in ASCII format instead of tagged binary.