by Mark Fischer.
With the update from 3.06 to 3.07 the viewing of submissions of assignements with grade type "None" returns a coding exception on get_grade_item(). The error is on line 1322 of /mod/assign/locallib.php in that it attempts to get the decimals of a non-graded item. If you edit the assignement and make it a grade type "Point" you can view the page properly.