It should give you a submit button when you finish. I'll check it now. That's a mighty good score to lose. I've noticed that sometimes you have to make sure you're definately logged in before playing otherwise that can happen too, a bit of a bug I think. Hopefully I'll be upgrading the arcade soon.
Sussed it. I played it all the way through. Scored 45 and ended the game on level 10. It seems that if you actually "beat" the game then you can't submit the score! A game bug rather than an arcade bug. I'll remove the game and add another couple instead. Thanks for the warning. EDIT: Deleted