5
I read that post, it just wasn't too clear. :)
I'd be happy to help out and test PHP5 and XOOPS. When I transitioned to PHP 5 on my dev server, all of my sites made the transfer just fine. Based on the errors I've seen after installing XOOPS on my server (PHP 5 rc1), it seems to mostly be type-casting issues. I just found out about XOOPS last week, so it would take me a bit to get up to speed, but I'll take a read through the Dev Info on the site, see if there is any way I can help out, if you need it or want it. :)
D