Mega 2560 R3 + Shield Ethernet R3 = problem upload sketchs (SOLVED)

paravion:
UPDATE: I'm a newbie, however, it would appear these avrdude errors appear if the 2560 has the Ethernet shield mounted while attempting to upload the sketch to the unit.

If the 2560 has no shields attached, I can upload the test code successfully, after which I unplug, attach the Ethernet shield, plug in again, add Ethernet and voila. Pretty awesome being able to ping an Arduino board...

Is this behaviour normal? Do all Arduino's need to be bare of shields, in order for the sketch to upload?

Excellent ! is the answer to the problem, my mega worked perfectly but the ethernet shield connect , had the same error. Change the usb to one of higher quality cable and it worked ! Thank you !