IN-BATTLE TRANSFORMATION

I'm trying to set it up so that one of my characters can transform into a stronger character during battle. i had a tutorial on it, but every time i try to transform, it gives me an error that says "event script referenced a battle animation that does not exist" i'm using RM2K3. any help would be great. Thanks.

it's a battle command linked to an event. and the event removes the original character, saves their level in a variable, and places the other into the party. This is just how the tutorial said, if you know any more effective ways i'd love to know 'em.

There seems to be some issue with removing the original party member. cuz it shows the animation just fine, but when it supposed to replace the character with the other, I get that error.

Also does it help to say that I converted an RM2K project to 2K3 and am working with blank battle character sets and rm2k monster art to make the battle style in the game similar to the one in RM2k? well not blank battle characters, but they're nothing but the blue BG.