[repost, please ignore the privious one]

I think I found the solution to the problem, it’s related to PHP open_basedir and Plesk. Here’s how I solved it:

Place this information in
/home/httpd/vhost/DOMAIN/conf/vhost.conf:

<Directory /home/httpd/vhosts/DOMAIN/httpdocs>
php_admin_value open_basedir none
</Directory>

Replace DOMAIN with your domain dir.

Now wpmu 0.1.1 works out ot the box 🙂