I've connected my Tool through a USB Hub, and now I get Error Messages and Inconsistent Results while Programming and Debugging

Tools and devices should be connected directly to a USB port on your debugging PC. If this is not an option, you may reduce/eliminate problems by:

Note: The AVR Dragon should be connected through a powered USB hub. This because the power supply on the Dragon can be too weak if the motherboard does not provide enough power. If the Dragon times out or freezes, then the hub might be of too low quality.