Just got my Viper GC chip today. Chip is 0447 and programmer is 0502. When trying to use Viper Loader, I too would get the "viper gc was not found" error. I tried all the usual things, then I noticed on the programmer that on the db25 connector, two pins on the end ere not soldered to the circuit board. Pins 13 and 25 to be exact. I soldered them myself, and the errors stopped and I was able to see the viper gc chip and read/write/compare with no problems. If anyone else is having this problem, check to make sure all pins on the programmer are soldered. Wish I had done that 9 hours ago. Anywho, mine works, and I'm happy.