Some API calls on beta cluster throw exceptions which eventually lead to a fatal error.

Exception:

2014-01-30 01:17:23 deployment-apache33 enwiki: [48af842e] /w/api.php Exception from line 84 of php-master/extensions/Wikidata/extensions/Wikibase/repo/Wikibase.hooks.php: Wikibase: Incomplete configuration: $wgWBRepoSettings["entityNamespaces"] has to be set to an array mapping content model IDs to namespace IDs. See ExampleSettings.php for details and examples.
#0 [internal function]: Wikibase\RepoHooks::onSetupAfterCache()
#1 php-master/includes/Hooks.php(206): call_user_func_array('Wikibase\RepoHo...', Array)
#2 php-master/includes/GlobalFunctions.php(3976): Hooks::run('SetupAfterCache', Array, NULL)
#3 php-master/includes/Setup.php(520): wfRunHooks('SetupAfterCache')
#4 php-master/includes/WebStart.php(153): require_once('/data/project/a...')
#5 php-master/api.php(44): require('/data/project/a...')
#6 w/api.php(3): require('/data/project/a...')
#7 {main}

Which then lead to the fatal error:

[30-Jan-2014 01:17:23] Fatal error: Call to a member function disable() on a non-object at php-master/includes/GlobalFunctions.php on line 2140
Server: i-0000031b
Method: POST
URL: http://en.wikipedia.beta.wmflabs.org/w/api.php
Cookie: XXXXXXX
Backtrace:
#0 php-master/includes/GlobalFunctions.php(2140): wfHttpError()
#1 php-master/includes/Exception.php(257): wfHttpError(500, 'Internal Server...', '[48af842e] /w/a...')
#2 php-master/includes/Exception.php(612): MWException->report()
#3 php-master/includes/Exception.php(686): MWExceptionHandler::report(Object(MWException))
#4 [internal function]: MWExceptionHandler::handle(Object(MWException))
#5 {main}

Note how line #1 of the fatal error stacktrace points to an error 500 generated by the exception.

Version: master
Severity: normal
Whiteboard: backlog