avrdude: stk500v2_ReceiveMessage(): timeout error on MEGA ADK

My son bought me a Arduino Mega ADK for christmas. We already had a Uno board R2 which was working fine. I am using the blink LED example outputting to pin13 but when I upload to tje Maga ADK I get the following
avrdude: stk500v2_ReceiveMessage(): timeout
then it seems to upload successfully. However I dont get this error with the Uno board. I have noticed on the Mega ADK a long pause before the TX and RX lights start to flash and I think it's this delay thats causing the error message. I am using a Mac Pro with OSX version 10.8.2. and Arduino version 1.0.3. The correct board is selected and the setting is /dev/tty.usbmodem1d21 Programmer AVRISP mk11. From a bit of googling around it appears others are having similar problems, but I can't seem to find a definitive answer. Any ideas?

Wrongway:
avrdude: stk500v2_ReceiveMessage(): timeout
then it seems to upload successfully.

Do you have to click upload a second time or do you get the "error" message followed by the upload starting?

No I don't need to hit upload a second time I get the error message followed by the upload. Doesn't happen on the Uno though.

So then, what's the error?

A big line in red had me worried. I thought possibly its a fault with the board. Especially when I found a few similar posts where this error message started appearing after a while.