Okay, I played FO3 using FOMM earlier yesterday. I quit to go do some errands. I returned and tried to get back on the game, clicked on the shortcut to FOMM and got a pop-up window with the following message:

"FOMM has encountered a problem and needs to close. We are sorry for the inconvience."

I've reinstalled the game and FOMM, played the game until all of the DLC's kicked in and still get the same message.

I need help as I play the game everyday and don' t want to be stuck playing a vanilla game!

Edit: Found a workaround... downloaded the old FOMM and it works fine. Still strange that the FOMM would suddenly behave oddly like that!