MediaWiki internal error.

Original exception: exception 'MWException' with message 'Detected bug in an extension! Hook efGoogleAnalyticsHookText failed to return a value; should return true to continue hook processing or false to abort.' in /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/Hooks.php:155
Stack trace:
#0 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/Skin.php(978): wfRunHooks('SkinAfterBottom...', Array)
#1 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/SkinTemplate.php(455): Skin->bottomScripts()
#2 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/OutputPage.php(1572): SkinTemplate->outputPage(Object(OutputPage))
#3 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/Wiki.php(376): OutputPage->output()
#4 /var/www/vhosts/wikiflashed.com/httpdocs/w/index.php(118): MediaWiki->finalCleanup(Array, Object(OutputPage))
#5 {main}

Exception caught inside exception handler: exception 'MWException' with message 'Detected bug in an extension! Hook efGoogleAnalyticsHookText failed to return a value; should return true to continue hook processing or false to abort.' in /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/Hooks.php:155
Stack trace:
#0 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/Skin.php(978): wfRunHooks('SkinAfterBottom...', Array)
#1 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/SkinTemplate.php(455): Skin->bottomScripts()
#2 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/OutputPage.php(1572): SkinTemplate->outputPage(Object(OutputPage))
#3 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/Exception.php(164): OutputPage->output()
#4 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/Exception.php(191): MWException->reportHTML()
#5 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/Exception.php(289): MWException->report()
#6 /var/www/vhosts/wikiflashed.com/httpdocs/w/includes/Exception.php(348): wfReportException(Object(MWException))
#7 [internal function]: wfExceptionHandler(Object(MWException))
#8 {main}