What did you do to cause this?
Try to view an attachment with a space, !, bracket, comma, or other symbol in its name.
What page were you on?
What PHP and MySQL versions do you run?
Describe the defect:
Attachments with only the characters a-z, A-Z, 0-9, -, _ and . work correctly. Attachments with other characters in their names can be uploaded, but cannot be viewed or deleted - a 404 page is returned.