Healing when leveling?

I really want to make my characters heal when ever they level, especially when i am making the enemies rather difficult.  i am testing it as i go, and i dont want to make the enemies less difficult, but making my characters heal when they level would make things go alot smoother. can anyone help? i saw a post that said something about scripts, but when i type the script someone gave me, it came out as an error and when i posted it to the materials section, it never read the script for some reason.  can anyone help?

or this one in case you'd need the extra functionality in the future

http://forums.rpgmakerweb.com/index.php?/topic/24573-level-extension-v110/

If you have problems with importing the scripts, make sure you're importing it on a new script under materials