Thread:Project:Support desk/Fatal error: Call to a member function addWikiMsg() on a non-object in /home/username/public html/wiki/includes/specials/SpecialLinkSearch.php on line 82/reply (27)

If it shows up as 1.18.0 in Special:version, then you didn't install 1.18.1. Make sure that all files from your 1.18.0 install are over-written by the 1.18.1 files (Except LocalSettings.php)

This issue should be fixed in 1.18.1 (1.18.1 uses $out, but its supposed to use $out. The issue in 1.18.0 is only half of the $wgOut -> $out change went through, breaking things badly for that special page)