I have a weird problem running on Arduino ...
Here is the story, I just start using the UNO board .. i can run the example of "Getting Started w/ Arduino on Mac OS X" (http://arduino.cc/en/Guide/MacOSX) and the board indeed works! However, when i try to input some code on the panel, there is something wrong about the Arduino software whenever the 2nd character is typed. The software crashed like this !! 
Can someone tell me how to fix this ?