Hi Andy,

Nope, not a single crash occured after more than 20H of game since I re-installed my system with Seven 64 bits.
These crashs seems really related to 32 bits OS or 32 bits drivers.

thanks for the feedback anyway, better late than never ;)
++

I've reinstalled OS in Seven Pro 64bits, no crashes occured after 4H of play

Confirmed.
When I encountered this behavior, I always was inside a building (on a room or on the top) or close to an obstacle (tree, rocks)
Never had this on a "open space" area without obstacles