Here's what happened:
I received a transfer ID before I hit the submit button. When I did, I got a red error message saying: "Limit reached or not enough bitcoins in your account." Non-the-less the entire amount (around 50BTC) did to to my working blockchain.info wallet.
...
I would have thought that Mt. Gox would have some of these UI bugs by this time which is what this looks like to me. Oh well.
You were not supposed to click on the Submit button as you had already withdrawn your coins. They should change the UI to not display the button after the screen refresh.