Email cron job

in my mail I get these errors ... how can I fix it?

<div style="border:2px solid red;padding:4px;width:600px;margin:0px auto;">
<div style="text-align:center;background-color:red;color:white;font-weight:bold;">Error</div>
<div style="text-align:center;">Database connect failed</div>
</div>

Fatal error: Call to a member function getParam() on a non-object in /home/xxx/public_html/snowboard/inc/db.inc.php on line 83

www.predagrafica.com/snowboard

/bin/sh: line 1: 25204 Killed                  /usr/local/bin/php -q cron.php

Your mysql server was overloaded. You need make some improvements for mysql - http://www.boonex.com/trac/dolphin/wiki/HostingServerSetupRecommendations

Check the MySQL is up and running.