strange message has appeared

The message below has suddenly appeared on a website I'm building on
selmamccormack.com/selma/#welcome . .
Any ideas what this is and how to get rid of it?. Thanks

Strict Standards: Declaration of JParameter::loadSetupFile() should be compatible with JRegistry::loadSetupFile() in /home/selmamcc/public_html/selma/libraries/joomla/html/parameter.php on line 0

Hello,

This is just a harmless warning. Go to Site > Global Configuration > Server and level down the Error Reporting parameter.

Thanks