I had this problem too!....
Luckily there's an easy fix and I now have 2 characters at lvl 99, tons of gold and also hacked health pots.
I believe the code that caps free players at lvl 15 causes problems and confuses the game causing it to reset. I tried a lot of things I.e. editing monster kill count.
After a long haul I finally found a way to beat the code.
(Warning!!! Contains spoilers below)
Basically you want to follow the main quest up to the point you get capture and thrown in a cell (where you first meet amarisa). After completing this quest leave the sewers and save your game (backup too!!) Then go ahead and edit game values like normal.
For some reason this stops all the resetting and I've beaten the game with no problems.
If ppl continue to have problems I'll happily upload a save file for you guys.
