XF 1.1 server log error

[xml]

i found tons of this error message in server error log:

ErrorException: Indirect modification of overloaded property XenForo_Visitor::$_nodePermissions has no effect - library/XenForo/Visitor.php:179

what does it mean ?

 

[Jake Bunce]

What version of PHP? Is there a full stack trace in your log?

Admin CP -> Tools -> Server Error Log

 

[xml]

What version of PHP? Is there a full stack trace in your log?

Admin CP -> Tools -> Server Error Log

php 5.2.17

Stack Trace:
#0 /home/vbcom/public_html/community/library/XenForo/Visitor.php(179): XenForo_Application::handlePhpError(6, 'a:26:{s:18:"sti...')
#1 /home/vbcom/public_html/community/library/XenForo/ControllerHelper/ForumThreadPost.php(41): XenForo_Visitor->setNodePermissions(6, Array)
#2 /home/vbcom/public_html/community/library/XenForo/ControllerPublic/Forum.php(49): XenForo_ControllerHelper_ForumThreadPost->assertForumValidAndViewable()
#3 /home/vbcom/public_html/community/library/XenForo/FrontController.php(310): XenForo_ControllerPublic_Forum->actionIndex(Object(XenForo_RouteMatch))
#4 /home/vbcom/public_html/community/library/XenForo/FrontController.php(132): XenForo_FrontController->dispatch()
#5 /home/vbcom/public_html/community/index.php(13): XenForo_FrontController->run()
#6 {main}

This error kept logging for 2 hours only yesterday according to what i saw in the server error log