This is my 2nd playthrough and its been awhile since my first go. I do remember there being problems with the Dark Brotherhood also the civil war quests....as well as some others. A quick search on the net and I haven't really been able to find anything concrete. I was able to avoid problems my first time around...but all that means is I know i will end up playing differently this time and really don't want to end up screwing myself over. Especially after having a glitch in the companions questline that would have kept me from EVER finishing it what so ever...I was lucky enough after trying for days to find a solution that was not on the wiki so I put it up there myself. Don't want anything like that to happen again.