Go and download Boss (http://www.nexusmods.com/fallout3/mods/10193/?) it will reorganize all your .esp's in the correct spots with the Boss's Master list. After i began to use it, CTD"s were largely reduced afterwards. All .esm files MUST go before all of your .esp files and if you use NMM, read the side panel and check the Masters for that specific .esp. Hope this helps!