After installing osCommerce on a clients website, the osCommerce installation gave a number of errors. Searching the web and forums, let to the discovery that you have to have register_globals on and safe_mode off.
Add a vhost.conf file with the following entries:
<IfModule sapi_apache2.c>
php_admin_flag register_globals On
php_admin_flag safe_mode Off
</IfModule>
and then reconfigure the webserver:
/usr/local/psa/admin/bin/websrvmng --reconfigure-vhost --vhost-name=<domainname>
and restart the webserver:
/usr/local/psa/admin/bin/websrvmng --restart