I was surprised to see so many having trouble with corrupt game saves and such. I did a complete play though and only had a few crashes and only 2 bugged quest - Come fly with me and Oh Papa. The reason I think that I had no problems is that when I started playing NV I did not have FO3 patches or DLC on my HDD. Both games use so much of the same code I wouldn't be surprised that is were the conflict is. I know some will dismiss that idea but I've seen patches conflict before. Me and some friends had to redownload the patch for Far Cry Predator after a patch for RB6-Vegas. Different studios for Ubi but their patches conflicted.

My suggestion is to get rid of everything and start fresh. Delete both FO3 and NV DLC. Delete corrupt game saves. Clear the 360's cache (system settings>Memory>press Y for device options>clear system cache) Load game but decline the patch. Clear the game cache (hold RB+LB+X as game loads) . Don't start game just return to dashboard. Sign into XBL, redownload NV DLC, start game and accept patch. Play and Pray!!

i'm sorry but someone has to say it.

you don't know what you're talking about. the dlc bug is caused by bodies falling through the floor and the game not being able to load them.

everyone, don't delete all of you FO content...

i am sorry but u haven't a clue as i don't have FO3 on this 360 it is on my other 1 and i have hit the DLC error no less than 21 times ranging from 2hrs into the game to 60+hrs and i have hit some of the other big bug's and have now stoped playing and have even taken my copie back t store and got 2 diff games that i can play not wait to play

First, both of you need to learn to read. The title of the thread says "possible solution". And until the dev's say what is wrong, everyone is just guessing at what is causing the problems. I see threads here with different ideas on what quest or place is causing the DLC crash.
Also, I did not say delete everything from FO3, just the DLC which can be redownloaded at any time. You can keep your FO3 game saves or you can transfer all FO3 stuff to a flash drive then remove the drive. Easy stuff to do!
The things I listed to do are painless and for those who don't mind giving things a try!

Okay well this is a "possible" solution that won't work. And this is painless? You said in your original post to delete everything (just because you said only the DLC after it doesnt change the fact you said everything- but i get what you are saying) that has to do with Fallout 3 and New Vegas. Plus, you can't redownload your New Vegas DLC. Once you delete it, it's gone forever. Also, why do all of this when a patch is bound to come out in under a month that will fix this? People waiting, like me, for a long time already, can wait just a little bit longer.

Sorry, I'm speaking out of frustration here..

You can redownload DLC to the same console it was purchased on or a code was used. Press Guide button>Settings>Account Management>Download History>select file to redownload. I just did this and it took under a minute to do.

Okay, you proved me wrong on that one. Actually, thank you for telling me that because I did not know that!

It's "out of the box" thinking, but I cannot, in any way, see this as being the cause.

I used to think it was faction score related, but now, I think that bodies falling through the game world and disappearing sounds extremely likely.

Provided the error message is accurate, that is.