I created this thread in the Bugs & Suggestions category:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1294536128/0#0
I will edit it to add the point about you trying with Ubuntu and using 0021. I do not know if anything would result from it but it does not hurt to include all the details.
Does anyone reading this have an Uno they could try this out on? I am curious about whether it is a Mega 2560 problem or both of the new Arduinos being affected.