To make special settings proceed as follows:

1. Log in as admin.
2. "Einstellungen"
3. "http Spezial"
4. "für einen Kunden ändern"
5. enter: php_admin_value open_basedir none

Maybe it's necessary to switch off the SafeMode.

To this the same procedure as above is required, though another entry has to be made:

php_admin_flag safe_mode Off