How to disable open_basedir in plesk without breaking/commenting your current httpd.conf basedir lines.
# touch /var/www/vhosts/yourdomain.com/conf/vhost.conf
Now we edit the file and we add the following,
# vi /var/www/vhosts/yourdomain.com/conf/vhost.conf
<Directory /var/www/vhosts/yourdomain.com/httpdocs> php_admin_value open_basedir none </Directory>
Once you finish adding the mentioned lines, its time to reconfigure and restart the webserver config.
# /usr/local/psa/admin/sbin/websrvmng -v -a