Only if you run the scenario with the sSU pad. The other scenario should run without any additional add-ons.You need the latest Space Shuttle Ultra version found here: Space Shuttle Ultra v1.25
Yes.
It didn't fix the problem. Try downloading and installing it yourself. Maybe some crucial files were left out in the uploading.
It worked fine for me. BTW Urwumpe, the sparks (for lack of a better word) looked cool after separation, my daughter questioned it, but she didn't know that the SRB worked like that (and she hates it when I'm right).
Your Ares 1-X seems to ignore the TARGET_HEADING setting in the scenario at my end. The default scenario launches to 2 degrees instead of 90.
I did that test already before uploading it, also maybe it didn't occur to you, but there is at least one person who managed to install and use it. A missing file in the installation would mean nobody can use it.
Also, what does orbiter.log say?