Thread:Project:Support desk/Hooks array for event 'ArticleDeleteComplete' is not an array!

I can't seem to delete any pages.

Internal error View or restore one deleted edit? Hooks array for event 'ArticleDeleteComplete' is not an array! Backtrace:
 * 1) 0 /var/www/html/mediawiki-1.18.1/includes/GlobalFunctions.php(3631): Hooks::run('ArticleDeleteCo...', Array)
 * 2) 1 /var/www/html/mediawiki-1.18.1/includes/WikiPage.php(1742): wfRunHooks('ArticleDeleteCo...', Array)
 * 3) 2 /var/www/html/mediawiki-1.18.1/includes/Article.php(1513): WikiPage->doDeleteArticle('content was: "#...', false, 766, '')
 * 4) 3 /var/www/html/mediawiki-1.18.1/includes/Article.php(1358): Article->doDelete('content was: "#...', false)
 * 5) 4 /var/www/html/mediawiki-1.18.1/includes/Wiki.php(496): Article->delete
 * 6) 5 /var/www/html/mediawiki-1.18.1/includes/Wiki.php(255): MediaWiki->performAction(Object(Article))
 * 7) 6 /var/www/html/mediawiki-1.18.1/includes/Wiki.php(640): MediaWiki->performRequest
 * 8) 7 /var/www/html/mediawiki-1.18.1/includes/Wiki.php(547): MediaWiki->main
 * 9) 8 /var/www/html/mediawiki-1.18.1/index.php(57): MediaWiki->run
 * 10) 9 {main}

what does this mean?

MediaWiki	1.18.1 PHP	5.3.3 (apache2handler) MySQL	5.1.61

http://www.mwusers.com/forums/showthread.php?18798-Hooks-array-for-event-ArticleDeleteComplete-is-not-an-array!