"Unknown Lua interpreter error occurred!"

Very curious error, is there any way to sort out where this error stems from? I’m trying to recycle some code froman out of date version 2.8 tool, but I can’t figure out which part of the code I can salvage without knowing which parts don’t actually work. I figured if it was a difference in api version I would get a bunch of “undeclared such-and-such” errors, but got this on first attempt to run it.