I was in vault 22 at the end of "There stands the grass" and Ed-E got in the way of the inferno and got ko'd. Now he is nowhere in sight. When I went to see Mr. House, I was told my companions had to stay outside, and he is the only one I curently have. Did anybody else have a problem like this? I tried looking for him in the vault and he is not there.

he might be back in Primm, inside the store where you first found him.

I checked there and also back at the hotel room in Novac. I fear he will be lost forever. And he had some good loot too.