I'm sorry you're having some trouble. For starters, you'll want to make sure that the particular device(s) you are trying to install your app on have been added to your Device list on your Apple Developer Site and included in the AdHoc Provisioning Profile for that app. If you are unsure how to do this please read our article on setting up your test device here — http://support.magplus.com/entries/21042956
If you device is already setup and you are still having trouble, let me know and I'll try to help you further.
Mag+ Support Team