by Guillermo Madero S..
Hi Tiffany,
I would start by modifying the line so it starts with "/usr/bin/", like so:
/usr/bin/wget -q -O /dev/null http://mysite.com/public_html/courses/admin/cron.php
This is because php is usually under /usr/bin (you may want to send a ticket to the Bluehost support department and ask about the location of php).
Also, make sure that the installation is not restricting to only executing cron via command-line: