Printer won't print unless usb is unplugged...

So yea...as you can tell by the title it's a very interesting problem. We have a Xerox Workcentre 5638 printer hooked up to a Windows 7 and Windows xp machine via USB Switch. This thing has given us nothing but trouble. When we first received it:

- The driver to install was labeled "RNDIS/Ethernet Gadget". We fixed that by enabling the USB Printer Port on the machine.

- Now we installed the printer, everything looks ok. Printer says "Ready" but when we print ANYTHING!!!...It doesn't print. It doesn't show up in the queue on the computer nor does it show up on the printer Job Status screen. HOWEVER, when we unplug the usb cable from either the pc side or the printer side, like MAGIC, the printer will print the document. We have contacted our vendor tech support and anyone else who could normally assist us, but they all seem to stupid to fix this problem. SO Major Geekers, I look to recruit you guys to handle this mission. Send backup, snipers, and if you have one Incredible Hulk...please smash this POS like in Office Space. Thanks!!!!