Re: Emails From Contact Form
George will explain this better than me but it has something to do with hits to your 'thank you' page that don't come through people visiting or filling in your form. You can test this by tyoing in your url to your thank you page then I bet you get a blank email as you did above. George told me that even a SE robot hitting on that page could set it off.
He did do something for me though that seemed to calm it down, so maybe he will come along and help you when he sees this post.
Don't aim for success if you want it; just do what you love and believe in, and it will come naturally.