In real life, setting the computer's program to repeat every minute instead of every day would be a hard mistake to make. Additionally, no kids (with no experience programming computers) would be able to notice it in a printed version of the program (it would not be obvious, it would say something like "pause 60000" or "wait 60," rather than "repeat every minute").
The devices that the kids hook the computer up to (which have supposedly been at the school for a while) would have to support the signal and programming of the (supposedly brand-new) computer. This would take some modification that would be beyond the capacity of an elementary school. Furthermore, the devices are shown hooked up to the computer through a modular cable. In the 1990s, they would almost certainly be hooked up through some variation of RS-232 (all of which use D-sub connectors).
The computer screen shows Greek letters in random order when the machine itself boots up. In reality, computers use Roman letters and digits via ASCII binary codes when they boot up.