After using arduino.exe for a couple of weeks I then got the message above in the subject line everytime when attempting to run the program. After searching the internet for a solution I deleted the file preferences.txt (Windows XP) in Users/Your User Name/AppData/Roaming/Arduino. This enabled me to start the program. Going back to the location where the file existed, I see that it was again created, Nonetheless, arduino.exe continues to start up without a probelm. Not seeking help here; just documenting this for reference. - Scotty