[JonathanLKS]

Are you using a USB to Serial converter? We've found some USB to Serial Converters will either die or fail to upload one way or another. If your using the latest IFI Loader, and your code was able to be uploaded when using a different computer, this sounds most likely.

If your using a serial port, or you are sure your USB to Serial converter works, the only other thing I can think of that hasn't been mentioned, is sometimes the controller just won't let you load code and you have to do a master reset (happened like once during the 3 years I've been in FIRST), hold both prog and reset, then I think let go of either prog or reset (can't remeber), but the right one will leave only the green power light flashing, when it stops flashing you can let go and load code.