"Add Attachments" button does not work while grading Tests & Quizzes

1. Login as an instructor and go to published copies in Tests & Quizzes.
2. Select scores from the drop-down menu beside an assessment
3. View student answer by clicking on one of the student's name in the column "Name"
4. Click on "Add Attachments" below the "Comments for Student"
5. The Add Attachments window does not pop-up

Screenshots:

http://www.evernote.com/shard/s562/sh/2492ea5b-38e3-4862-b1f4-7b3c485bdd8a/634742745a2401723ad5d003c748ba0f

http://www.evernote.com/shard/s562/sh/b00360f4-2abb-44e1-9759-cb09ad046c5f/96c9560217e3bdd64c2fb7b7f2f6d345

http://www.evernote.com/shard/s562/sh/139e1a8d-eb6b-436d-94d7-0f8e285847f7/287cf59d1b700132dcfe470dea479a0a