I used this code for iPhone iOS 5.0 device. And everything was OK:
self.mapView = [[[MKMapView alloc]init] autorelease];
mapView.delegate = self;
mapView.frame = CGRectMake(0, 0, 320, 414);
[myView addSubview:mapView];
MKCoordinateRegion zoomRegion = MKCoordinateRegionForMapRect(MKMapRectWorld);
MKCoordinateRegion adjustedRegion = [mapView regionThatFits:zoomRegion];
[mapView setRegion:adjustedRegion animated:NO];
Then I tried it on iPhone 6.0, and it crashes at the string [mapView setRegion:adjustedRegion animated:NO];
*** Terminating app due to uncaught exception 'NSInvalidArgumentException',
reason: 'Invalid Region <center:+0.00000000, +0.00000000 span:+176.06470039, +360.00004292>'
What should I change in my code?
EDIT
In your case
[mapView regionThatFits:zoomRegion];
it create issues.. remove it :