What does it mean if I get an error that says 'Fatal error: Call to undefined function mysql_connect()'?

If you get an error like "Fatal error: Call to undefined function mysql_connect()" when trying to install Kayako, it probably means that MySQL support has not been enabled for PHP on your server (ie the PHP module php-mysql has not been installed).

You can confirm where or not the MySQL module is present by accessing a phpinfo() page for the server. The MySQL module (if installed) will appear in the phpinfo() as shown below.