Sorry I wasn't very thorough -
This is an existing Plesk 11.0.9. I did not attempt to upgrade, all though I did apply Update #55 after this happened to see if maybe that would fix it. That went smoothly but did not fix it.
The only thing I remember is I was modifying some vhost permissions, but I'm fairly certain I did not do anything outside of the vhost dir. but, I'm having a sneaking suspicion now that this is a permissions issue.