Ok. I cd'd to the directory, and tried to run run.bat. Didn't work; came up with the same error. I also tried to run the arduino exec. from there. Same thing. I checked for the rt.jar file. It was there. Just out of curiosity, I tried to run it. Should it have run properly? Because I tried to run it and it said: "Failed to load Main-Class manifest attribute from [......\ directory ---> rt.jar]. Hmmm...