I too am having this issue.
Whenever I run the program, I get an error message that says:
"Dungeon Siege III.exe has stopped working.
A problem has caused the program to stop working correctly.
Please close the program."
I did not have this issue before the 12MB patch that was downloaded by Steam earlier this week (I haven't tried playing the game before now, but I was able to play before the patch)
The error message in the Event Viewwer is listed as:
Faulting application name: Dungeon Siege III.exe, version: 1.0.0.0, time stamp: 0x4e038749
Faulting module name: Dungeon Siege III.exe, version: 1.0.0.0, time stamp: 0x4e038749
Exception code: 0xc00000fd
Fault offset: 0x0027368f
Faulting process id: 0xd2c
Faulting application start time: 0x01cc33bc456af80b
Faulting application path: f:\program files\steam\steamapps\common\dungeon siege iii\Dungeon Siege III.exe
Faulting module path: f:\program files\steam\steamapps\common\dungeonsiege iii\Dungeon Siege III.exe
Report Id: 85817764-9faf-11e0-a4fd-d4efb160190f
This is with the Retail version of the game, purchased from Gamestop, with the Gamestop pre-order items applied to the game.
Doing some google searching, I saw that this error might be caused by DEP so I attempted to disable DEP for DS3 but that did not help.
I also attempted to send this message and my DxDiag to the email address listed above, but it was bounced back by your mail server.