I actually had this happen to me four times tonight with the Wii game (tonight is the first time I've ever experienced the problem though). I got one of the grave digger ghosts stuck behind the same wall TWICE, another stuck behind a gate, and a Gozer worshiper stuck behind a sealed door.
The first time I was forced to reset the level. The other three times, through a lot of patience and dumb luck, I was able to wrangle the ghost and trap it despite the glitch.
It seems to me, where the Wii version is concerned, that the game becomes prone to glitches when you attempt to “speed run” through levels.
I even managed to crash and lock up my Wii the other day trying to play through “The Collector” battle too quickly. I had died and re-spawned, skipped over the dialog, and jumped into the battle while the console was apparently still thinking a little about the previous battle (the screen said that Egon was down despite the fact that the level had reset).
When I skipped the dialog/cinematic at the beginning of the level, the dialog continued to play for a second, regardless, and clashed with the characters talking during the battle itself.
The next thing I know The Collector is spitting out way more enemies then he usually does, the sound cuts out, and the picture goes black (followed by some sort of null read error frozen on the screen).
I had to disconnect the power cord in order to shut down the system, but when I started it back up agian everything was fine.
When I played through the game the first time (at a normal pace), the only glitches I encountered were cosmetic.(*winston)