Not a bug Posting thread causes issues (1.1)

I'm currently using XenForo 1.1, and posting a new thread fails with this message :

The following error occurred:

Argument 1 passed to XenForo_DataWriter_Discussion_Thread::_discussionPostSave() must be of the type array, none given, called in /home/dekema2/public_html/library/EWRporta/DataWriter/Discussion/Thread.php on line 7 and defined
XenForo_Application::handlePhpError() in XenForo/DataWriter/Discussion/Thread.php at line 183
XenForo_DataWriter_Discussion_Thread->_discussionPostSave() in EWRporta/DataWriter/Discussion/Thread.php at line 7
EWRporta_DataWriter_Discussion_Thread->_discussionPostSave() in XenForo/DataWriter/Discussion.php at line 391
XenForo_DataWriter_Discussion->_postSave() in XenForo/DataWriter.php at line 1385
XenForo_DataWriter->save() in XenForo/ControllerPublic/Forum.php at line 490
XenForo_ControllerPublic_Forum->actionAddThread() in XenForo/FrontController.php at line 313
XenForo_FrontController->dispatch() in XenForo/FrontController.php at line 132
XenForo_FrontController->run() in /home/dekema2/public_html/index.php at line 13

I'm not sure if XenPorta has anything to do with this. Thanks for any help.