Yes... Um,
1. You're attempting to check if a vassal has a law. Vassals don't have laws, titles do. I think you're in the wrong scope for that
2. You're syntax is wrong on the "if"
Code:
immediate = {
if = {
limit = {
WHATEVER YOUR LIMIT IS SUPPOSED TO BE. I think you want to check for any vassal that holds a title that is in the same realm as a top liege which holds the title of e_byzantium. I'm not so sure how to write that but the limit you're putting there is a bit off. Vassals don't have laws, titles do... but you're checking to see if the vassal has that law.
}
EFFECT of who is limited... What happens to the person that has this limit.
}
}
3. You put down 'is_triggered_only = yes. I don't know if you have something else calling this (a decision, another event, a cb_type effect, an on_actions, etc...). If nothing is triggering it, then this will never happen.
These are just a few things I've found so far...