I presume the message "Status: Notice: Trying to get property of non-object in .../wordpress/wp-content/plugins/slickquiz/php/slickquiz-model.php on line 69 Not Published" is just some sort of runtime flag you've put up in the development? You get that when saving a draft of a new quiz...but not saving a draft of an existing quiz...
From my colleague, Fil Downs:
I'll commit a fix...