Really sorry about this issue. Our BTC assets were mostly concentrated in Mt. Gox accounts recently. And our withdrawal wallet is out of funds.
We are currently trying to divert some Bitcoins from Mt. Gox to our wallets.
I have marked your transaction as "Pending Approval", so that you can cancel it any time and get your money back. I suggest you to withdraw in smaller amounts instead, such as 100 BTC, so that your funds won't get stuck when similar things happen.
This is not a good sign....... Site down.