Bob and David didn't know that the season 4 bloopers weren't on there, they were supposed to be. Apparently there's an outtake where Bob blows up at Jay during the wishing well skit, and he's so upset it didn't make it on to the DVD. They might be putting the missing stuff on their site for people to buy/download right from them.
Here's the interview where they mention it:
http://filmforce.ign.com/articles/54...html?fromint=1