CGRectMake - App crashes after install from xcode doesn' crash when re-launched on device

Question

I'm building an app to iOS 4.0 and it crashes upon launching when xcode installs it. It crashes when loading my root view controller. It crashes at:

- (void)viewDidLoad {
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor blackColor];

    UIButton *button1 = [UIButton buttonWithType:UIButtonTypeCustom];

When I step through the breakpoints it ends up in CGGeometry with CGRectMake

CG_INLINE CGRect
CGRectMake(CGFloat x, CGFloat y, CGFloat width, CGFloat height)
{
  CGRect rect;
  rect.origin.x = x; rect.origin.y = y;
  rect.size.width = width; rect.size.height = height;
  return rect;
}

When i re-launch the app from the device it's fine. The debugger and console give no indication of a problem. What else can I do to find the source of the problem?