I use SimPE mostly for editing sims, memories, changing names, interests, surgery and other simple stuff. But since i started after a year ago to play sims 2 again, i think i installed the newest update, the commit button for saving your changes won't work. It looks like it works but when i want to exit i get a window asking if i'm sure i wan't to exit cause it isn't saved bla bla bla. I clicked a thousand times and exited with that window asking thinking it's saved anyway but my game showed that nothing was changed. I thought it was a glitch but no, it happened every time. Any advice?

You have to click commit and then save - are you doing that? It's not just click the commit button, that just commits the programme to saving, not actual saving.

You should use the latest SimPE which is called 'For Everyone'. Then as maxon says commit-then save. Save is up to the top left under file or Ctrl S.