I created an iOS app and want to distribute it Over-The-Air. I followed this guide:
http://help.apple.com/iosdeployment-apps/mac/1.1/?lang=en-us#app43ad77ea
We did experience the very same error message when trying to install an iOS 5+ app to an iOS4.3.5 phone. Did you also check deployment/build targets and target architecture to match the device(s) showing that issue?