Thread:Extension talk:Scribunto/Template import and Script error - "Lua error: Internal error: The interpreter exited with status 1."/reply (3)

The information in the debug log includes debugging information, which is why there is so much of it. You should be able to ignore any line beginning with "TX" or "RX".

The script error you're getting now does sound like bug 46294, as you seem to have already noticed. When you attempted to apply the fix, did you look at the "diff" view and make only the changes shown, or did you download the entire files (which might include other unrelated changes)? If the former, what were the three errors you received?

I don't know which "installation file" you're referring to, but the same version of Scribunto (and MediaWiki, for that matter) that is running on WMF wikis is available via git.