Arduino 12 ran okay in Vista using "Run as administrator".
In Windows 7 Beta Build 7000, that wasn't enough. The troubleshooter added an option "Vista Compatability Mode" and the program launched. The Beta sent a troubleshooting/problem message to Microsoft.
Another report after I'm able to communicate with the Arduino.
The first time I tried to compile a sketch, the status windows gave a number of java error messages. I closed the program and re-launched it. This time I was able to compile and load the sketch to the arduino. The serial monitor seems to work, also.
One anomaly is that the serial port that Seven assigned to the arduino was 4. I've had 1,2,3,23,24 under Vista, but 4 is a new one.