Problem with Modded Youtube App

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http://forum.xda-developers.com – Hi, So I installed the modded Youtube 4.2.16 Build v2 by theos0o to allow me to play HD videos while on 3G network, my biggest problem is that the app keeps getting uninstalled and gets back to the default youtube app whenever I restart or shutdown the phone !! I also have a problem trying to keep the videos playing while on another screen, the video just stops although I ticked on the "Screen off Playback" Why does the app revert back to the default version on it's own?? :S Any ideas? (HowTos)