Just going to make a place for me to put Errors that I've come across that are somewhat vague in their meaning and have needed to troubleshoot myself.
The given key was not present in the dictionary.
This likely means you linked an action or "Kill Priority" to an NPC that doesn't exist. Check everywhere that you have NPCs named and make sure you spelled them correctly or included ones you may have removed.
Error parsing: [Code thing here], message: No coercion operator is defined between types 'System.Double' and 'System.String'.
This happens when you're using Temporary Variable in one of your code boxes (not sure what else to call them.) Generally, you want to set your "Temporary Variable Types" to "Double." It defaults to "String," so make sure to change it. I'm sure the other types have uses as well, but I am not sure.
"Boss action sequence must have at least two entries that are not at the same time."
EDIT: As Yellowfive said below, this is actually when you have not checked "Once" on a boss Action and it repeats forever. Read his post below to Understand it better.
Two factory-generated intervals overlap. Can't do that.
This is my least favorite error. This means you have NPC Intervals that overlap with each other. Check the intervals, their start times, and how long they are. Make sure they don't conflict with each other. It may be that you need to make a special interval for when the two other intervals overlap.
Index was outside the bounds of the array.
This one I am not totally sure about yet. I encountered this one when I did not give an action an amount. When I gave it an amount of 0, it seemed to work. I'll update this if I ever encounter it again.
EDIT: Okay, I encountered this one again. I found out what was causing it in this case, which seems different than the last time I encountered it. I had NPCs that spawned at a certain time and were alive a period of time past the Fight Length. If I removed them, reduced the time period they were alive, or increased the length of the fight, this error went away.
Overall, I think this error is definitely my least favorite of the bunch. If it could just tell me what Index is outside which array, that'd be very nice. wink wink nudge nudge
That's it for now. Hope this helps someone!