My Direct Messages Are Not Viewable Online...

For the past week or so I have not been able to view my direct messages (both sent and received). I can receive them fine via my cell phone, but when I go to view them online only the tabs "Sent," and "Received" are viewable. I cannot actually go directly into the direct message.

I am currently using Mozilla Firefox on Windows Vista to go on the Internet.

HELP, please!