I can't compose an email because the diaglog box does not come up, all I have is send and subject, HELP!?

Where I normally can type the message, it's all grayed out. The only fields I have to type in are send to and subject. I can't figure it out.

I can't compose an email because the diaglog box does not come up, all I have is send and subject, HELP!?
Check if your connection is too slow.