Time Machine would only be of marginal help for you in this situation anyway, unfortunately. It's heaven for restoring files you accidentally deleted, or getting back to an earlier revision of a file you screwed up, and you should totally turn it on like right now. But unless you wanted to nuke your system and restore it to the state it was in 24 hours ago, it wouldn't do much for you in this case.
If the AVC Intra Decoder is just a Quicktime component, you should be able to find in, and remove it from, /Library/QuickTime.