Pam claims her birthday is on October 21st, 1959. However, the secretary claims that she just turned 21. If Bob & Doug were framed for kidnapping Pam on October 10th, 1983, Pam would be 11 days shy of her 24th birthday, 3 years after she turned 21.
When Bob and Doug go to the brewery and find Pam stuck in her Volkswagen convertible in the gates of the brewery, she says something to the effect of "Help I'm stuck and I can't get out". She is in a Volkswagen convertible and the top opens mechanically from the inside, which would be easily to unlatch and put down.
When Claude is talking to Bob and Doug, and telling them about Pam's birthday party, and how to get to it, he refers to her as his daughter. Pam is actually his niece, and at most his step-daughter, now that he has married her mother.
When Doug McKenzie types in the code to get the floppy from the safe, he hits a vertical row of numbers on the keypad. However, when Ted and Brewmeister Smith views the video, it shows a different video of Doug McKenzie's hand hitting a different sequence of numbers.
The first time Doug plays the game, the display shows Pam Elsinore "Level 6" 211,059 and she exclaims her birthday is 21-Oct-59. The screen clears and redraws showing John Elsinore "Level 7" 040483 (no commas) and Pam Elsinore "Level 6" 070483. When Pam looks at it the second time (later scene), she says 04-Apr-1983 is the date her father (John) died. The 070483 does not appear the second time and there is no explanation for what - if anything - happened to her on 07-Apr-1983.
When Bob and Doug are pulled up to the signs showing them which direction to go (The Insane Asylum, the Castle, the Brewery, etc) the first shot of them sitting in the cab show the dice hanging from their mirror have the sides showing the two dots. After a quick view of the signs we are shown the boys in the cab again but this time the dice have changed and we see the sides showing four dots on each one.
After Bob and Doug push the Volkswagon through the Elsinore Brewery main gate and stop their van, there is a shot from behind the gate (now mysteriously closed) via the security camera. It is obviously a different gate, with a different bar pattern.
Before entering Elsinore Brewery, Bob and Doug look up at the building and the Elsinore sign. The cut shot is clearly a fake picture which doesn't resemble the real building, and the "Elsinore" lettering is sized and centered differently in the two shots.
When the loaded tractor-trailers pull out of the indoor dock to go to Oktoberfest, the trailer doors are all closed. The trailer in Dock #1 is only about a foot from the wall to its left. Trailer doors require 4 or 5 feet of space to close. The driver of the truck would have to pull the trailer out of the dock before closing the doors - the trailer doors wouldn't and couldn't be closed inside the dock after loading.
At the beginning of the film, when Bob and Doug are running from the movie theatre, the shadow of the camera, crane and cameraman are visible for a moment on the street, next to the cop car they pass by.
When Bob and Doug arrive with the Toronto police at Oktoberfest, they are stopped by a Peel Regional Police officer. Oktoberfest in Kitchener-Waterloo is in the Region of Waterloo, and is jurisdiction of the Region of Waterloo Police Service.
The definition that Claude Elsinore gives for catatonic schizophrenia (referring to Pam) is word-for-word the exact same as the definition that Brewmeister Smith later gives for paranoid schizophrenia (referring to Bob and Doug). Although one may think that this is because of Claude Elsinore's lack of education in psychology, the definition is actually a better fit for catatonic schizophrenia than for paranoid schizophrenia, so Brewmeister Smith, the psychiatrist, is farther off than Elsinore.