Robots.txt actually sorted itself out, not sure if it was saving settings on a theme, or what, but no error now.
As for the permission settings, I’m not 100%, but it may have been my error the entire time. I set up the VPS a few months ago, and learned a tremendous amount in that week (came from shared hosting, zero experience with servers). I likely set the group / owner to www-data:www-data (the user who executes php), when learning how to make it work. I don’t remember doing this, but it was information overload, so I likely did it once, and never again, until the update failed, and I had to re-install from scratch, thus set folder permissions again. Stuart told me it had to be that user because of the writing to the cache directory, which makes sense.
The only real issue I see at this point, is troubleshooting the error. Calling render() on a non-object is a pretty bizarre error for something permission related. I know how crazy errors can be, but any better handling of that situation could save people a lot of time.
That being said, my issues (pertaining to installing), are all sorted, so this can be marked as resolved.
