[kh99]

Looks like that's caused by someone trying to exploit a security issue that's been fixed in later versions. One change that was made (I assume) to fix it is in packages/vbforum/search/socialgroupmessage.php, around line 511, the parts in red were added:

	protected $type_globals = array (
		'nocache'            => TYPE_UINT,
		'messagegroupid'     => TYPE_ARRAY_UINT,
		'categoryid'         => TYPE_ARRAY_UINT
	);

I can't guarantee that's the only change needed (or that there aren't other security issues with that version), so it's probably best to update to the latest version when you can.