I have several USB drives and as stated above semaphore timeout error is lack of communication from drive to comp. I got this error with one of my drives because of an ALI chipset in the case which is known to cause problems. If your case and comp can handle firewire try that and see if it works out.
i changed cases to one that supports firewire and that worked like a dream. i'm so excited i can burn again. thanks for all of the help.