J-BusinessDirectory - After upgrade to 3.6.4_2 is again unable to save aplication settings.

After upgrade to 3.6.4_2 is again unable to save aplication settings.

Regarding this post: http://www.cmsjunkie.com/forum/unable-to-save-application-settings/

I have update k2.php file

$task = JRequest::getCmd('task');

with 

$task =JFactory::getApplication()->input->get('task').

 - but us not working

I have uninstalled K2 - still not working.

Regarding JomSocial

I havent in /plugins/system/jomsocialupdate/jomsocialupdate.php 

bellow line:

$task = JRequest::getCmd( 'task' , '' );

Before upgrade was all OK.

Hi,

The problem cannot be caused by an upgrade. It must be caused by a system plugin. You must deactivate them one by one to see which one is causing the problem.

I found plugin, which causes a conflict, it is

Thank you for help.