IRQ conflict between USB and NIC SCO 5.0.7

I have a SCO 5.0.7 server.As there is no parellel port ,printing is done via USB port.
After loading the Network Card driver ,during booting the server gets hanged and the NIC driver is not loaded.If the USB ports are disabled the NIC driver gets loaded.
As both USB and NIC driver are essential for our system please provide a solution in this regards.
I have loaded the maintainence pack -5 CD in the server.
The BIOS doenot have settings for setting the IRQ's.
Thanks