after a long session of testing for the error i have found out,this script is not fully compatible with EQUAP cause if you have the scripts in order you still need to learn the skill through RO job/skill in order to master it by EQUAP and the sp cost wont show up right in the menu.
also skills that dont level at all work fine in battle, but say you have the skill HEAL and its max level is 5,it doesnt matter if you level it or not everytime you use it in battle you will get the error above it doesnt matter if EQUAP is on or not you will still get the same error.if you take this RO job/skill out completely everything works fine. im thinking one of my scripts may be confliciting about it but im not sure of which one it could be if there is one causing problems at all. this is a issue for me dunno bout anyone else,due to the fact that the player party members besides the protagonist learn skills through this script while the protagonist learns them through EQUAP.
EDIT2: probably would help if i added the cade right?
# change SP considering skill level
battler.sp = old_sp - (@skill.sp_cost *
actor.get_skill_sp_cost_factor(@skill.id)).to_i
@status_window.refresh
the error comes from the line starting with actor.get_skill