Hey Johannes,
Try the Gui that I posted in that thread, here again for your reference:
http://e2e.ti.com/support/low_power_rf/f/667/p/245454/885052.aspx#885052
I didn't personally make the changes but I believe it is suppose to run better on Win 7. I'm running Win 7 64 bit with that version and I do see fewer issues.
Try that version and let me know if it's any better.
Thanks,
JD