Uploading code to Arduino with XBee shield

I'm trying to confirm that my Xbee setup is working (Two Diecimilia boards w/ xbee shields), so I tried to upload the Physical Pixel example from the tutorials section on the main page. For both by boards I am getting the

avrdude: stk500_getsync(): not in sync: resp=0x00
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51

error that other people had. I have my jumpers in the right place, and I followed the instructions, but to no avail. I confirmed this on another PC in the lab at school - same error.

This might be unrelated, but when I upload "Blink" (uploading works without the Xbees shields in place), it works fine without the shield, but stops blinking with the shield in place. The voltages on the Xbee are 3.5V, which is close enough to 3.3 so the circuit is OK. Anybody have a similar problem?

Where'd you get the XBee shields?

I got the kits from NKC and built them. Could be an issue there, but they are both acting in the exact same way.

You might want to ask NKC for help as I think he's including some extra parts in the kit that prevent sketches from running when the shield is in place. The design of the shield includes some optional components for allowing the ATmega to be reset remotely using one of the digital outputs of the XBee module, but with the module's default configuration, it keeps the ATmega constantly reset.

Thanks. Will do.

nickD, I mounted the XBee shield on a Freeduino board with the blink sketch and the sketch is running with the board in place. Please, send me an email to help at nkcelectronics dot com and we can try to debug your problem.

i have two xbee shields mounted on two arduino boards, they communicate alright with the example given in the tutorial (with L and H sent from one gets the other with a led on 13 to go on and off) when they are connected to two different pc via usb. but there is nothing going on when i replace one usb by a 12 v dc supply (the receiver on which i have moved, of course, the arduino jumper). any clue why???

Can you tell if it's related to the XBee at all? What if you upload a simple LED blink application the board and try to run it with the 12V power supply? What kind of board is it?