Print jobs sent to wrong printer

I have a Epson DFX-5000+ attached to a local compaq presario and shared over the company’s small LAN. I also have a Toshiba 452 that is networked directly on a netgear switch. The Compaq has a ip address of 1.1.1.35 and the Toshiba has a ip address of 1.1.1.36. We use accounting software made by Epcior called Vantage. Sometimes when we sent a print job from vantage to the DFX it will print on the Toshiba. If you log out and log back into vantage it prints just fine. My question is whether this is a network problem (maybe the IP address are too similiar) or a software problem. Epicor claims it is not their software.