Script does nothing

Downloaded the files and adjusted the clients.php
But then the skript does nothing. I can even use the example:
# usr/bin/php usr/local/nagios/libexec/check_unifi.php -H 192.168.2.1 -u USER -p PASS -P 8443 -s -m uplink -a AP01 -w 200 -c 100
And get nothing.
Any ideas?
(sorry, rating required)