After performing the command apt-get install php5-cgi, mysql is not longer enabled.  Since the tutorial is for suphp, and most of the questions that lead you here are related to ISPCONFIG, an optional step should be included to reinstall the php5 modules.  To reinstall mysql, I issued the command apt-get install php5-mysql php5-mysqli --reinstall.

I discovered this issue after having a successful Mambo installation that now would give site not available error with a 1 at the bottom of the page.  Then running the mysqlcheck.php script also found on this site showed that the mysql.connect function could not be found.

Thank you for providing such excellent tutorials. I find them very useful and complete.