line 2249 currently reads:
$row .= '<td align=right>'.$grades_by_student[$student]['student_data']['weighted'].'%</td>';
it is missing the double quotes around right as in the other instances (see line 2246 for an example)
line 2249 should read:
$row .= '<td align="right">'.$grades_by_student[$student]['student_data']['weighted'].'%</td>';