MediaWiki internal error.

Original exception: [cb2a088b] /wiki/Special:UserLogin/signup Exception from line 1072 of /home/lgviewer/lookingglassviewer.org/includes/specials/SpecialUserlogin.php:
Backtrace:
#0 /home/lgviewer/lookingglassviewer.org/includes/specials/SpecialUserlogin.php(210): LoginForm->mainLoginForm(string)
#1 /home/lgviewer/lookingglassviewer.org/includes/SpecialPage.php(631): LoginForm->execute(string)
#2 /home/lgviewer/lookingglassviewer.org/includes/SpecialPageFactory.php(488): SpecialPage->run(string)
#3 /home/lgviewer/lookingglassviewer.org/includes/Wiki.php(298): SpecialPageFactory::executePath(Title, RequestContext)
#4 /home/lgviewer/lookingglassviewer.org/includes/Wiki.php(602): MediaWiki->performRequest()
#5 /home/lgviewer/lookingglassviewer.org/includes/Wiki.php(467): MediaWiki->main()
#6 /home/lgviewer/lookingglassviewer.org/index.php(49): MediaWiki->run()
#7 {main}

Exception caught inside exception handler: [249bb7c9] /wiki/Special:UserLogin/signup Exception from line 212 of /home/lgviewer/lookingglassviewer.org/includes/Hooks.php: Detected bug in an extension! Hook BrettCrumbs has invalid call signature; Parameter 1 to BrettCrumbs() expected to be a reference, value given
Backtrace:
#0 /home/lgviewer/lookingglassviewer.org/includes/GlobalFunctions.php(3877): Hooks::run(string, array)
#1 /home/lgviewer/lookingglassviewer.org/includes/OutputPage.php(1616): wfRunHooks(string, array)
#2 /home/lgviewer/lookingglassviewer.org/includes/OutputPage.php(1551): OutputPage->addParserOutput(ParserOutput)
#3 /home/lgviewer/lookingglassviewer.org/includes/OutputPage.php(1489): OutputPage->addWikiTextTitle(string, Title, boolean, boolean, boolean)
#4 /home/lgviewer/lookingglassviewer.org/includes/OutputPage.php(2229): OutputPage->addWikiText(string)
#5 /home/lgviewer/lookingglassviewer.org/includes/Exception.php(406): OutputPage->showPermissionsErrorPage(array, string)
#6 /home/lgviewer/lookingglassviewer.org/includes/Exception.php(606): PermissionsError->report()
#7 /home/lgviewer/lookingglassviewer.org/includes/Exception.php(678): MWExceptionHandler::report(PermissionsError)
#8 /home/lgviewer/lookingglassviewer.org/includes/Wiki.php(470): MWExceptionHandler::handle(PermissionsError)
#9 /home/lgviewer/lookingglassviewer.org/index.php(49): MediaWiki->run()
#10 {main}