Factual error: The equation written on the board does not come out to be "11", in fact, it's not really solvable because it doesn't have 2 sides, just a "?" on one side.
Continuity mistake: After the campers take over the camp, many counselors are tied to trees. When the kids are putting honey on Lars, the left strap of his tank top falls down. In the next shot of Lars crying with the deer, the strap is back upon his shoulder. (01:09:19)
Audio problem: During the Apache Relay Race, the boy who is swinging down the rope screams. But if you look closely his mouth is not moving at all.
Continuity mistake: The stack of books falls over when Roy breaks into the room. However, when they leave, the same books are stacked perfectly.