I cant seem to figure out how to get the Create Archive button to work for my mod...am I missing something?

Edit: I press "Pack Files" but then it just closes the window.

Just wanted to pop in and say that I'm having the same issue, so you're not alone. I don't have any idea how to fix it, though.

I've got the same problem, I hope there is a solution.

The Solution I found is trying to upload to steam, then cancelling after the bsa is made. Makes a nice bsa for you and you can package that in a zip yourself.