[Plugin: Sphider for WordPress] Commandline not working?

I’m using the plugin and it seems to work perfectly with WP 3.3.2
As the reindex is triggered only when there is a page update, i want to set up a cron job on our server. I have tested the commandline but it does not seem to do anything:

cd /var/www/site.com/htdocs/wp-content/plugins/sphider/admin/
/usr/bin/php spider.php -u https://site.com/page5 -r -d 2

PHP seems to run the page but nothing is happening. Anyone else having this problem with the plugin version of Sphider?

https://www.ads-software.com/extend/plugins/sphider/