gpib won't communicate

hi all.

I have 2 identical usb-GPIB adapter, and two different PC with the same acquisition software written in LabView, in the first machine, i can use both usb-GPIB interface with no problems.

on the second PC, the first interface works perfectly, the second one, instead, is recognized perfectly in windows device manager, but when i try to communicate with my instruments, the software says "oscilloscope was not found, check the cable or the instrument", what can i try??

thanks for the support. David