CGRect Frame Issue

CGRect Frame Issue

I keep getting a reoccurring issue while testing on iOS 7, I cannot figure
out if its a BETA bug that has not been properly addressed or if its my
code, or still if its a configuration problem.
I am trying to animate a UIView,
In my .h i have defined it like this
IBOutlet UIView *MainView;
@property (strong, nonatomic) IBOutlet UIView *MainView;
And in my .m this is the code. Its not a connection issue as the opacity
(alpha) animation works just fine.
[UIView animateWithDuration:4.3 animations:^{
[settingView.view setFrame:CGRectMake(160, 0,
self.view.frame.size.width, self.view.frame.size.height)];
MainView.alpha = 0.3;
MainView.frame = CGRectMake(-160.0f, -40.0f, ScreenSize.size.width,
ScreenSize.size.height);
}];
Any thoughts? Thanks a million!