Continuity mistake: When Gus heads to the bathroom at Mel's house he is carrying a bag of ice. The next shot of him, he is standing at the urinal and the bag of ice is sitting on the top left of the urinal. The next shot is from the top of the urinal, with Gus is still using it, and the bag of ice is gone. (01:02:05)Rochelle McCarty
Other mistake: In the final game of the movie, Jerry's Lumber is deliberately making errors to let Nelson score a run. In the shot where they show Marcus as the third base coach and Nelson rounds the base to go home, you can see that he never actually touches third base and cuts it off by a few feet. (01:15:25)
Other mistake: In the final game, after Gretchen has struck out for the first time, look carefully and you will see Nelson is running out of the dug-out like he is next to bat. Then in the next scene, suddenly it is Jarrett up to bat instead of Nelson.
Deliberate mistake: The Benchwarmers originally had only three players, and then only one who could actually hit. Despite this, none of the (supposedly competent) little league coaches chose to simply walk all the players and force an out.
Audio problem: When Brad's team is taking ground balls, he is hitting with a wood bat but it is making a metal bat sound.