So I just downloaded Point Lookout
and Fallout 3 now says "begin P.L. but start over and previous saves will be overwritten"

?

Does this mean that I cannot play Point Lookout whilst I have not finished the main quest? (i have not done so)

Considering my research on other DLC's (such as Brotherhood of Steel) there are certain things you can or cannot do before vs.
after you finish the main quest... otherwise you are screwed.

Nevermind.
I did my little google thing and it seems 0 kill (O.K.) to dive right in.

XBOX 360
I had a feeling this was going to be a problem.

To reiterate:
I have NOT finished the main quest of Fallout 3, and decided to DL 'Point Lookout' anyway.

1) i was given a one time chance to decide "do you want to overwrite "everything" or do you not want to, in order to begin Point Lookout?"
2) I chose not to, considering I did not want to take the chance of deleting all progress in my main quest.
3) Ever since then, there is simply no way to begin Point Lookout.
4) If Point Lookout is supposed to appear on the main quest map somewhere, by all means, point it out for me!
5) Why is everyone else able to do this easily, and i can't find the menu option for Point Lookout?

So did you fix it...??

Cheers

NO Daniels, nobody "fixed it" for me, but thanks for the offer.
Apparently, it takes a good 5-10 minutes for the DLC to kick in and actually show up on the main quest's map as a new assignment.

What do you mean by "everything?" What was the exact wording?

This is weird. I just downloaded Point Lookout today and I had another message similar to yours OP. Mine said, "This save relies on items that are no longer available, are you sure you want to continue?" I thought to myself well this cant be too bad, and I started playing. It turns out that this actually caused me to lose all of the items that I had gained from the Operation Anchorage DLC. Not only this, but my save file then failed to recognize that I had ever done Operation Anchorage! Is this supposed to happen when downloading Point Lookout?

WoW, that definately shouldnt be happening. Normally that message is associatied with a save with DLC's activated ... then you deactivate them , and try and run the save from used to have that content activated.

Who was the service you downloaded from? (this is console? and wich one?)

It's this then. Michael Bates (and OP) you must've accidently deleted a DLC, which, frankly, at least for me, is hard to do by accident. I get this message because of the way I must load DLC to avoid a glitch in the Pitt on 360.

Bates, stop.... then redownload the dlc, then reload a save before getting that message.

doofmaczemy: check your dlc location to make sure that you indeed have all that you purchased. It is possible you accidentally deleted a dlc. Re download it, then reload a save before the crazy began, and you should get all your stuff back, in addition to being able to go to PL. Be warned, PL on the 360 is laggy sometimes and a little crashy. Save often.