Taiyokou

Hi! You're good at spriting, right? Nice avatar by the way!

I know I've been trying to get in touch with him

Sorry, can't help you if you're ROM's corrupted. If you like, though, I can send you a Fire Red ROM that has all pokemon from generations 1 to 6. If you want it, just PM me. But be warned that it's very
glitchy though!
www.pokecommunity.com/showthread.php?t=334997

What causes the error and what happens when the error occurs?

Have you tried using karatekid's Gen 3 Hacking Suite? It's a great tool if you want to add pokemon from newer generations into your hack.