Ardinator:
In my mind that points towards an error in the Arduino 1.0.1 software.
In my mind it points to an error in the only thing that is different from the normal Arduino IDE. From their web page:
No modifications of the Arduino environment are needed, simply install the SiLabs USB drivers ...
Oops. A modification to the environment. Device drivers typically need access to low-level operating system functions. People would be screaming if the normal Arduino IDE crashed the entire computer every hour. It just doesn't.