[falko]

I've just experienced the same behaviour on Mandriva 2006, therefore I added

<Directory /var/www/sharedip>
    Options +Includes -Indexes
    AllowOverride None
    AllowOverride Indexes AuthConfig Limit FileInfo
    Order allow,deny
    Allow from all
    <Files ~ "^\.ht">
    Deny from all
    </Files>
</Directory>

to /etc/httpd/conf/httpd.conf.

I've also modified the ISPConfig installer so that it will write this section to the httpd.conf in future versions automatically.