That is it...You have added repos from MeeCatalog which include the Harmattan SDK repo...My suggestion would be is to remove those repos using MeeCatalog and then trying enabling developer mode... Next time, since you know you require developer mode, its best after a reflash first to enable developer mode then do other things P.S. MeeCatalog adds the repos into /etc/apt/sources.list.d/ too so its not separated...