The error msg says it all:

Fatal error: Call to a member function attribute() on a non-object in D:\htdocs\ezp\installs\ezpublish-4.6.0-ent\extension\ezjscore\classes\ezjscajaxcontent.php on line 243
Fatal error: eZ Publish did not finish its request

It happens e.g. when someone tries to put in a rich text field a link to an object that has got no node yet - most likely via bad import scripts