uploading problem with atmega644p and gen7 1.3.1

Good evening,
I make a RepRap Prusa with GEN7 card and atmega 644p. As in the tutorial about gen7 of the site, I loaded the Arduino IDE and test program setuptest.pde. I loaded the file into the atmega. When I listen to the port I read the instructions without any problems. But now when I want to load the firm of the printer, the upload stops at 85 or 90% and finally issue a timeout on the connection. Unable to upload another file. Can you help me to solve this problem?

Thank you

Check for cold solder joints on the serial pins, try powering the board off the USB rather than ATX (ie. move the power jumper to the one close to the USB-Serial connection), try restarting the computer. Try a ferrite ring or cylinder on the USB cable to help with EMI. If you have a rather large ferite ring you can wind it around a couple times to increase the EMI filtering. Load the ATX supply down on the 5V line at least an amp or two to stabilize the power supply.

no cold solder joints on the serial pins.
I move the power jumper to the one close to the USB-Serial connection (option 3 in tuto Gen7 board 1.3.1).
I restart my computer.

result : OK

Thanks for your help