I have the same exact problem here. I think it has something to do with the gamepad not supporting USB 2.0 ports.
I guess installing a new USB PCI works. Was it USB 1.1? Is there a non-hardware way of fixing it?
Hmm... I don't have a USB PCI card here, but I *do* have a spare hub! And, hey, it worked too! Yeah! Thanks for the suggestion.