Having similar problems but it's only when I try out a few things on my software.
Specifically it will freeze when:
Changing the type of Arduino in the tools section
Trying to compile any script
Upload to board
Is this a java version thing? I've tried just running the bat and the exe separately...
Operating system: win xp sp2
Arduino v10
Arduino NG168
Here's an error that occurred when trying to change board types:

Also how do you check to see what is using which COM port. When I try and change the Arduino from COM port 8 to 3 or 4 it says those ports are being used... but I don't see anything showing up when I'm in the Device Manager. Windows only shows various MSDos ways to change COM ports... and I'm not about to start messing with that.