All of the above posts are great, however not so much if you have a very large project, and it has several nested structs referenced everywhere. I found a solution which gives you the exact actor class, and the variable causing the error. I didn’t post this, I’m just reposting it because this page is much easier to find for others 
(Link - https://www.reddit.com/r/unrealengine/comments/l8qaa4/isshortpackagenamepath_error_while_packaging)
