Trying to get property of non object in mod_assign

Viewing mod/assign/view.php?id=198&action=view

Notice: Trying to get property of non-object in /home/fred/www/repositories/i25/moodle/mod/assign/locallib.php on line 3433

Call Stack

#	Time	Memory	Function	Location

1	0.0003	245056	{main}( )	../view.php:0

2	0.2208	33978032	assign->view( )	../view.php:53

3	0.2209	33981352	assign->view_submission_page( )	../locallib.php:501

4	0.3774	42054600	assign->view_student_summary( )	../locallib.php:3665