"Creating default object from empty value" Errors

Am getting the same error.

Using wordpress 3.7 & Buddypress 1.9

I get the same error with BP GTM System 1.9 and WordPress 3.8.

I temporarly fixed this setting default value :

if (empty($gd)) { $gd = new stdClass(); }
if (empty($gd->search)) { $gd->search = new stdClass(); }

@maxime O
but for all non-programmer.
in which php and where put the code must be pasted?