I've been trying to fix this bug in StickWars for months (I had beta access to OF 2.1) and just now found out the reason. For those of you using OpenFeint 2.1, make sure that your app doesn't have this bug.
It is tricky to catch because it only occurs the FIRST time you run your app on a device, and if you rotate it after the initial OF dialog has been dismissed. However, this will affect your new users probably pretty often, so you want to correct it.
Again, you can test it by deleting the app off your device, reinstalling it, and then loading it and trying to rotate it after dismissing the OF dialog.
The solution is listed http://help.openfeint.com/discussions/problems/265-exc_bad_access-the-first-time-i-run-my-app.
Or you can just copy the code I used. Add this in to your main AppDelegate before you attach your window to the cocos2d Director (the line that looks like this [[Director sharedDirector] attachInView:window];).
// this is to fix a bug with OpenFeint 2.1 that causes a bad_access on autorotate on the first run
UIViewController* controller = [[UIViewController alloc] init];
UIView* glView = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
controller.view = glView;
[window addSubview:glView];
If you are using OpenFeint 2.1, I suggest you check this out, and let me know if you see or don't see this bug. I'd like to give the OF people some feedback on this. Thanks!