Issue: An exception occurred: Call to undefined method vw_Plugins_Forum_Model_XF

I have to deactivate the wiki-addon:

An exception occurred: Call to undefined method vw_Plugins_Forum_Model_XF::statistics_blocks() in ../httpdocs/library/vw/XenForo/CodeEventListener.php on line 424

vw_XenForo_CodeEventListener::template_create() in XenForo/CodeEvent.php at line 58
XenForo_CodeEvent::fire() in XenForo/Template/Abstract.php at line 82
XenForo_Template_Abstract->__construct() in XenForo/Template/Abstract.php at line 105
XenForo_Template_Abstract->create() in WidgetFramework/WidgetRenderer.php at line 704
WidgetFramework_WidgetRenderer->render() in WidgetFramework/Core.php at line 519
WidgetFramework_Core->renderWidget() in WidgetFramework/WidgetGroup.php at line 105
WidgetFramework_WidgetGroup->render() in WidgetFramework/Core.php at line 519
WidgetFramework_Core->renderWidget() in WidgetFramework/Core.php at line 481
WidgetFramework_Core->renderWidgets() in WidgetFramework/Core.php at line 448
WidgetFramework_Core->_renderWidgetsFor() in WidgetFramework/Core.php at line 327
WidgetFramework_Core->renderWidgetsFor() in WidgetFramework/Listener.php at line 133
WidgetFramework_Listener::template_post_render() in XenForo/CodeEvent.php at line 58
XenForo_CodeEvent::fire() in XenForo/Template/Abstract.php at line 195
XenForo_Template_Abstract->render() in XenForo/Template/Public.php at line 110
XenForo_Template_Public->render() in XenForo/ViewRenderer/HtmlPublic.php at line 124
XenForo_ViewRenderer_HtmlPublic->renderContainer() in XenForo/FrontController.php at line 639
XenForo_FrontController->renderView() in XenForo/FrontController.php at line 158
XenForo_FrontController->run() in ../httpdocs/index.php at line 13