I don't really understand how the web2py cron an "external cron" work together. I have a crontab in my application cron folder that appears to run when I'm running web2py on my Mac.
But on my server, I have a regular crontab file (set up with "sudo -u www-data crontab -e") that executes web2py to run the crons. http://web2py.com/book/default/chapter/04?search=crontab#Cron It may be that when running Web2py with WSGI, web2py internal cron is disabled. I jsut don't really know for sure unfortunately.