It is probably something in extensions. Couldn't find anything in diff between wmf6 and wmf7.

[10-Jan-2013 23:33:23] Fatal error: Call to undefined method languages::getCode() at /home/wikipedia/common/php-1.21wmf7/includes/cache/MessageCache.php on line 622
Server: srv193
Method: GET
URL: http://test.wikipedia.org/wiki/Special:ZeroRatedMobileAccess
Cookie: optin=1; mf_alpha=1; centralauth_User=Brion+VIBBER; mfsecure=1; centralauth_Session=5827c231f8dd0e7f40b2fc2c896ef79d; testwiki_session=0538e0efee0b3dc7713c167bbbe0c974
Backtrace:
#0 /home/wikipedia/common/php-1.21wmf7/includes/cache/MessageCache.php(622): MessageCache->get()
#1 /home/wikipedia/common/php-1.21wmf7/includes/Message.php(670): MessageCache->get('zero-rated-mobi...', true, Object(languages))
#2 /home/wikipedia/common/php-1.21wmf7/includes/Message.php(431): Message->fetchMessage()
#3 /home/wikipedia/common/php-1.21wmf7/includes/Message.php(483): Message->toString()
#4 [internal function]: Message->__toString()
#5 /home/wikipedia/common/php-1.21wmf7/includes/Html.php(167): strtr(Object(Message), Array)
#6 /home/wikipedia/common/php-1.21wmf7/extensions/ZeroRatedMobileAccess/ZeroRatedMobileAccess.body.php(314): Html::element('a', Array, Object(Message))
#7 /home/wikipedia/common/php-1.21wmf7/extensions/ZeroRatedMobileAccess/ZeroRatedMobileAccess.body.php(53): ExtZeroRatedMobileAccess->beforePageDisplayHTML(Object(OutputPage), Array)
#8 [internal function]: ExtZeroRatedMobileAccess::onBeforePageDisplay(Object(OutputPage), Array)
#9 /home/wikipedia/common/php-1.21wmf7/includes/Hooks.php(255): call_user_func_array('ExtZeroRatedMob...', Array)
#10 /home/wikipedia/common/php-1.21wmf7/includes/GlobalFunctions.php(3856): Hooks::run('BeforePageDispl...', Array)
#11 /home/wikipedia/common/php-1.21wmf7/extensions/MobileFrontend/includes/skins/SkinMobileBase.php(51): wfRunHooks('BeforePageDispl...', Array)
#12 /home/wikipedia/common/php-1.21wmf7/includes/OutputPage.php(1999): SkinMobileBase->outputPage()
#13 /home/wikipedia/common/php-1.21wmf7/includes/Wiki.php(562): OutputPage->output()
#14 /home/wikipedia/common/php-1.21wmf7/includes/Wiki.php(448): MediaWiki->main()
#15 /home/wikipedia/common/php-1.21wmf7/index.php(59): MediaWiki->run()
#16 /usr/local/apache/common-local/live-1.5/index.php(3): require('/home/wikipedia...')
#17 {main}

It appears that zrma has no default CCs. Adding Arthur and Tomasz.

(In reply to comment #3)

It appears that zrma has no default CCs.

There isn't. If anybody wants me to add people, just tell.

Ah I fixed this in the configuration a while back. Reopen if it continues.