Have you been down this street, where the external works in the simulator but fails on the device? I have, and trouble shooting why it sometimes fails can drive one crazy. Well I recently notice an major reason why It has failed for us. Looking back, I can not believe we missed this in the first place.

The tip very simple is worth adding to your checklist when building or adding iOS externals to Livecode iOS builds.

Make sure that the standalone settings in Livecode for the iOS version is the same as the iOS sdk version, that built the external in xcode. (Aka if you built the external using iOS 4.3.0 then set the livecode minimum OS standalone settings to 4.3.0.) Yep can not believe I missed that either, but I did.