Hi, I've just installed vanilla on a server. I've installed it on its own domain, with php5 on debian 3.0, as a virtual host among other virtual hosts (on other virtual hosts i'm running mediawiki, wordpress 1.5 and wordpress 2.0)
sometimes, i get a "session_start" error, ps_files_cleanup_dir: opendir, on /var/lib/php5 (where the session files are put for this install)
anyway, I'm not sure exactly what's causing this error. the error appears to the end-user to be non-deterministic, but i figure there's some interaction between sites that's going on.