marlin software wont upload

so i have been having trouble getting the marlin software to upload to my Arduino Mega 2560. i keep getting this error and have no idea how to correct it. any help would be useful. this all started because i couldnt get Repetier to run with the CNC it kept giving me an Error box saying fatal error on the printer side. i checked all my conections and everything looks good so i figured it was a software problem and decided to upload the software to the Mega 2560 again and then i get this error and cant upload.

The fatal error is usually caused by not attaching the resistor to terminal T0.

If you bought it from me you do not need to reflash the arduino, it is no the issue.
Your arduino error is from using the wrong firmware arduino version combo. TRy the beta firmware, the most recent arduino .11, and make sure you have the ug8lib installed. there is a walkthrough on the firmware page.