MapKit not working on device but works in simulator

Question

I have added the frameworks (MapKit and CoreLocation) by selecting the Frameworks folder, right clicking, Add > Existing Frameworks.

The app builds in the Simulator (3.1.3) but fails on the Device (3.1.3) with the error:

ld: warning: in /Development/Sites/iPhone Projects/SwitchViews/MapKit.framework/MapKit, file is not of required architecture Undefined symbols:
"_OBJC_CLASS_$_MKPinAnnotationView", referenced from: __objc_classrefs__DATA@0 in NextView.o ld: symbol(s) not found collect2: ld returned 1 exit status

Answer 1

It seems that I just needed to restart Xcode to get things linked up properly.