New USB card, problems with iShuffle

[Davi]

Just bought a USB2 card as I was fed up with slow transfers, installed it, installed latest drivers.... now whenever I stick the iShuffle in, it appears in the "my computer" window for a few seconds, then disappears again, then after a while I get a warning message that the drive cannot be found (even though iTunes is still using it no problem) ejecting a drive correctly, be it a Datakey or whatever, produces the same result - any idea's?!