poller not running as user cacti (FreeBSD)

[steinex]

Hi,

i added the following line in /etc/crontab:
/5 * * * * cacti /usr/local/bin/php /usr/local/share/cacti/poller.php > /dev/null 2>&1

However, when it's running, the following error appears:
Fatal error: Call to undefined function: mysql_pconnect() in /usr/local/share/cacti/lib/adodb/drivers/adodb-mysql.inc.php on line 356

If I run the crontab as root, poller.php runs nicely and my graphs get updated.

I have mysql.so in my PHP-extensions.

Any hints?