Are you using FEditor? Mine never did anything like that, but I have had my FEditor spontaneously corrupt before. I'd try downloading again and trying again.
What's the new character's name?
EDIT: Downloaded your ROM.
Oh. You're using Buildfile?
I'm personally not too familiar with it, but I would advise with the following:
If you're new to this, I would recommend against messing with anything with eventing. Start with FEditor, then work your way to using the Event Assembler once you have more experience.
Lots of weird event-related bugs can happen (like yours) if you don't know exactly what you're doing.
By the way, I know that FEditor is getting a lot of flak right now, but the best remedy to its bugs are make tons of backups. If it screws something up, just go back to a backup and try it again.
Download just about anything you want here.