I have a problem that whenever I try to download, upgrade, or uninstall anything, on the confirm page under where it says modifications it says remove 7.1-7.1x pangu untethered. So when ever I try to confirm anything it can never get it.
I did, I wanted to see if I could use apps that require a higher ios version. Then I changed it back and accidentally deleted the file, but in case that happened I copied the file somewhere else so that if I messed up I could just paste it in there. Could that be the problem
You altered the system version plist. That is an extremely bad idea. You need to change it back to exactly what it was before you altered it. Only then will the problem be fixed with Cydia.
Did you change it back to exactly what it was before and then restart? If you restore, you'll have to restore to iOS 8.1.3 and that is not jailbreakable at this time.
I seem to remember when there where some who jailbroke on 7.1b2 (rather than the horrid 7.0.4) that editing the system version plist caused issues when trying to change it back. I believe after a certain point, Cydia seems to no longer acknowledge changes to that file. Best to just restore if 8.1.2 is still signed.