Hi someone, just a hunch but if you are crashing to desktop every time you hit escape, I would think its a graphics driver issue, i.e. when you are hitting escape, the display tries to change to a different diplay mode, possibly different resolution/refresh rate/3d, non 3d etc..
I'd make sure you have a nice up to date set of graphics drivers for your card installed and hopefully it will stop happening.

Anyway good luck with your game tell us how it all turns out :)