Basic question I forgot to ask: Is this script below the Battle System. If it isn't, make sure that you have this below the battle system, if it isn't already. The person who coded it did something really unusual (WHY, oh scripter, WHY would you COPY and PASTE the definition from the RTP??? WHY? >_< )
If that doesn't do it, then I'll need you to send me your script file (Data/Scripts.rvdata).