I just finished an install of OpenACS 5.8.0 with Postgres 9.3 on NaviServer 4.99.5 using the scripts referenced in footnote 2 above on Ubuntu 13.10. As suggested, oacs-5-8 was substituted for the version and packages in the script. This was among the smoothest and fastest installs of OpenACS I've done. After the base install, package installation of xowiki, search, and forums went without a bump. The only misbehavior came from the Developer Support package where ADP reveal and DB statistics seem broken. Pleasantly, Naviserver seems quite nimble.
As Jim referenced above, many thanks to Gustaf and the faithful few who have kept this project alive.