I had the same thing, downloaded patch this morning, missing DLC message, hit okay, continue and load saved game... boom a nice freeze just when I want to play most! Which is all the time!!!
However, I went to the game in the hard drive and deleted the new patch and the game is working fine for me now so I can play, has this not worked for others?
It depends really, some people have to completely start over. Others, like you for instance, resolve it quickly by deleting the patch. Other still, like me for instance, get the "DLC is no longer availible" gibberish, and are able to load their saves perfectly fine. It seems to react differently with each system, though those are the only three instances I've read about so far.
Also note: Some people who are aple to play their characters that were created pre-patch, like me, do have items dissapear from time to time. For instance, I'm working on a new main playthrough, because well, the special stats on my previous ones svck. Anyway, I just got into the NCR Safehouse to score the Ranger Combat armor, because let's be honost, it's some of the coolest looking armour in the game. :mohawk: Off topic, back on track, so I go to pick up the NCR Ranger Combat Armor, as well as the NCR Salvaged Power Armour, obviously over weight, I go to repare the NCR RCA, and its not in my Pip-Boy interface, yet I'm still egihed down by it, the Assault Rifle, Hunting Revolver, and Trail Carbine, as well as the NCR SPA are nowhere to be seen, so naturally, I get out of my Pip-Boy to check if I picked the items up (common mistake, think you picked something up and it turns out it's still on the ground :facepalm: ) the items weren't there, so I go back into my Pip-Boy and there they are, right where they should have been. Problem fixed, but it's a little annoying.