I'm putting games on my buddy's calculator, it's a TI-84 Plus CE, same as mine. I put the same games and jailbreak appvars that I have on mine. Except, the programs work fine on my calculator and on his, I get ERROR: INVALID because a variable or function was used that isn't valid.

What do I do to fix this.

Note: opening ArTIfiCE on Cabri jr. does allow for the games to open and run as they should but I shouldn't have to use arTIfiCE because it doesn't run on python software. Let me know if there's a fix or if I'll just have to stick with opening arTIfiCE.

arTIfiCE doesn't have anything to do with Python: it's used to make assembly programs run on TI-84 Plus CEs of any sort that have an OS version that doesn't otherwise allow assembly programs to be executed. We recommend a shell like Cesium or CEaShell so you don't need to keep running ArTIfiCE/Cabri Jr.

OS versions below 5.5 can run assembly programs without a jailbreak. OS versions 5.5 and above cannot.
You can use a shell like Cesium to launch programs, or a hook like asmhook to run programs from the homescreen.