Cron fails when calling hook_node_view
When you implement hook_node_view(), don't forget to check if you're really displaying the node using this code:

function MYMODULE_node_view($node, $view_mode, $langcode) {
  if ($view_mode == 'full' &amp;&amp; node_is_page($node)) {
    //Do something...
  }
}


This should correct your errors.