File could be corrupted. Drivespace was not designed to work on USB dongles native though it is certainly doable. I`ve heard of people losing packages to corruption, and it`s certainly possible that the dongle itself could have suffered some sort of damage. What type of compression are you using? what file system is the usb dongle? One other thing to investigate is the usb drivers, sometimes incompatibilities can show up. Was this drive compressed from files on this computer? or is this from another older installation?