I have been using progress bars on this course quite happily for a few weeks.
No issues. Today I went to add a new item to a progress bar.
It will not allow me to update. The screen just goes blank.

http://student.drouinsc.vic.edu.au/moodle/course/view.php?id=11100&sesskey=3ekH5Nhe9t&bui_editid=15734

is the URL of the screen it takes me too.
Have tried different browsers and different computers.
I can still access the "Overview of students" information and it is working fine.
I can still change progress bars on other courses. They work fine.
I have tried putting a new progress bar on this course and it won't configure either.
I am stuck.