Event fail...

Can I see the event block you changed?
I debug event code by opening a copy of the changed ROM in Zone Doctor and then exporting an event dump. That works as long as you don't save the ROM, since Zone Doctor likes to change all pointers to point to the CA bank for some bizarre reason (it will break the game bad).
Once I have the text dump of the events, I use Notepad++ to scroll to the spot I was editing and I look for weird stuff like 97-byte long action commands, indicating I forgot something. That approach really only works if you're working within vanilla command codes, though, because if you have a single original event command in the lot then Zone Doctor will crash.
The other option is to look at the event display by opening the ROM in FF6Tools (https://everything8215.github.io/ff6tools/ff6tools.html). I find that a little harder to navigate, though, and I don't know how to get an event dump text file out of it. It does handle custom event commands a little better than Zone Doctor does, though, and if you save and modify the JSON definitions you can tell it exactly what you want it to show for custom stuff.