Hi Michael
Trial and error methods are tedious, specially if you have to wait for cron. Try this.
If bitnami is sudo based, do this
$ sudo -i
[sudo] password for nonprivuser:
#
otherwise become root the usual way, either logging on straight as root or by
$ su -
Password:
#
After becoming root run
# ps uax | grep apache
root 1276 0.0 0.2 273960 14244 ? Ss Jul03 1:03 /usr/sbin/apache2 -k start
www-data 18200 0.2 1.1 305712 71344 ? S 16:39 0:17 /usr/sbin/apache2 -k start
....
You'll see one apache2 process owned by root and many other processes owned by somebody else, www-data in my case. Now become that user:
# su - that-somebody
$
Now try to run the cron.php in the command line:
$ /path/to/php /path/to/moodle/admin/cli/cron.php
I expect successful execution. Then you know whose crontab should execute cron.php. Othewise you have to dig further.
P.S. This is yet another case of a heavily packaged system, where you spend tons of time to get a small additional task done. If you do a vanilla installation like this
http://docs.moodle.org/en/Installing_Moodle_on_Debian_based_distributions, you know what you did and as a result you simple after installation tasks remain simple. That is my personal opinion.