[Mediawiki-l] Error after upgrading from 1.9.3

[Philip Beach]

Hello all,

After upgrading my wiki from 1.9.3 to 1.12 I receive the following error
message when I try to access the site.

Internal error

Detected bug in an extension! Hook efDspHook failed to return a value;
should return true to continue hook processing or false to abort.

Backtrace:

#0 /var/www/wiki/includes/SpecialPage.php(195):
wfRunHooks('SpecialPage_ini...', Array)
#1 /var/www/wiki/includes/SpecialPage.php(226): SpecialPage::initList()
#2 /var/www/wiki/includes/SpecialPage.php(337):
SpecialPage::resolveAlias('Specialpages')
#3 /var/www/wiki/includes/SpecialPage.php(412):
SpecialPage::getPageByAlias('Specialpages')
#4 /var/www/wiki/includes/Wiki.php(193):
SpecialPage::executePath(Object(Title))
#5 /var/www/wiki/includes/Wiki.php(45):
MediaWiki->initializeSpecialCases(Object(Title), Object(StubObject),
Object(WebRequest))
#6 /var/www/wiki/index.php(90): MediaWiki->initialize(Object(Title),
Object(StubObject), Object(User), Object(WebRequest))
#7 {main}
I tried commenting out all of my extensions in LocalSettings.php, but it
didn't help.

Does anyone know what may be wrong?

Thanks