The moodle page for more information tells you to turn on debugging.
Site Admin Menu -> Development -> Debugging
/admin/settings.php?section=debugging
Set to highest in drop down ... developer.
Then try whatever again.
Moodle should show a window on error. Copy and paste the text of that error to a text document on your local machine - NotePad/TextEdit on Mac). Save the text file for later reference.
Come back to this thread and respond ... here's the error ... paste text of error into the posting.
'SoS', Ken