If you're seeing PHP warnings or notices in your page out put like this:
<b>Notice</b>: Undefined variable: params in <b>/var/www/deki-hayes/skins/ace/Ace.php</b> on line <b>690</b>
You will want to change PHP's error_reporting variable so it doesn't display E_NOTICE messages. This can be done in one of two ways:
1) Prefered method: edit your php.ini file and set this
error_reporting = E_ALL & ~E_NOTICE
The restart apache so the change takes effect
2) Alternatively, you can put the following at the beginning of your LocalSettings.php file:
error_reporting(E_ALL & ~E_NOTICE);