*** Assertion failure in -[id<MKAnnotationView> layoutSublayersOfLayer:], /SourceCache/UIKit_Sim/UIKit-2380.17/UIView.m:5776

Question

I get a crash when executing my app on iOS 6.1.: I must have modified something I was not aware of and when I tried to execute the app on the iPod touch of my mum I got that crash and that happens even on the simulator with that version. What could it be and what may I do to fix it so that the app works both on iOS6 and iOS7?

Thanks,