When Ozzie uses the computer in Shady Glen's computer room, the scene is reused from the start of the film. (When he's "hacking" the website.)
One of the yellow vans used by Rafe's men to gain access to the school is seen parked by the front of the school when Ozzie drops off her sister. A couple scenes later this same van makes its entrance to the school when the security guard gets shot with a tranquilizer dart.
Bentley's guards are repeated; in other words, the same guard is in more than one place at once.
There are no graphical interfaces on web sites that allow users to hack.
Oz's computer is shown to be downloading at 115200 baud over a dialup modem. Not only is this not possible (dialup topped out at 33.6/56k), but the modem shown is v.23. v.23 modems operate at 1200 baud (1.2k) and were already very outdated by the time of this movie (33.6k) [v.34] was already in wide use.
When Bentley grabs the bug from Foster, he yells, "What the hell is this? Foster!" When it shows his face, and he is supposed to be saying, " - the hell is this?" he is just saying, "Foster!"
When Ozzie is skateboarding through the basement toward the electrical box, a crew member is seen to the right slowly crouching out of the way.
Misspelling of the word "wiener" in Ozzie's computer insult "weinerhead".