error while starting Arduino compiler

I've been using the Arduino compiler for quite a while now without any problems.
But with my new I7 machine on Win7-64-Ultimate, I sometimes have problems starting the compiler. It will show the blueish logo for a long time, and then come back with a small widown saying "an error occurred while starting the application".
Sometimes that's the end of it, and sometimes it will proceed and show me the usual Arduino window.
Any clues?