A commit made by Petr on 17th of September to fix undefined course config variables appears to have been taken care of wrong.

The $courseconfig variable didn't exist in the create_courses function because it appears to have been accidentally declared in the create_courses_parameters function instead.

This:
$courseconfig = get_config('moodlecourse'); //needed for many default values
Needs to be moved from the parameters function to the create_courses.