T-Racks--hardware chip not found

I have just purchased T-Racks, but my iMac is not able to locate the USB chip insert. Does anyone know how to get this to work? I get messages that the software can't be found at start-up, and when I open the software, it says the USB chip device can't be found. It is plugged into the built-in port (I thought plugging it into my USB hub could cause problems). If anyone knows the reason why, I'd love to find out. Thanks