Thank you for your suggestion, but it didn't help any.

Just for completness sake, I think I've narrowed down the problem a bit further. I learned that I can copy to the drive with no problem, but as soon as the copying is done, the laptop locks up and when I remove the cable, I get a "Delayed write failure" error message. I tried duplicating everything using the laptop's 1.1 usb ports, but I didn't get any error messages. worked fine...