MarlotteR06 If you have any custom careers, have the sims that have them quit the careers. Then pull the files for them out of your mods folder. You can try pulling them first, then giving the sims that had the careers new careers, but it is less likely to work. A lot of custom careers work fine until the game is updated but break afterwards and a lot of them never get updated so using them is risky at best.
Once done, test to see if the career panel works correctly. If it does, you can try putting the custom careers back in one at the time to find whatever one is broken and remove it permanently.
Hope this helps.
Info: luthienrising