SSH connection refused: Frodo XBMCBuntu

Hi all,

I'm trying to log in to my newly installed Frodo XBMCBuntu box, but it's not playing ball.

I can ping its IP address from a Terminal on my Mac laptop and get a perfect response.

Historically - with everything from Eden to a Frodo beta Openelec - I've always typed in 'ssh USERNAME@IP.ADDRESS.IN.HERE' and then it's prompted me for my user password. That's normal, right?

However, now it doesn't even do that. I simply get 'Connection closed by IP.ADDRESS.IN.HERE' and returned to the prompt.

Am I missing something obvious? Is there a simple reason why it would be doing this? It's got me dumbfounded; I'm used to screwing up the install itself, but I've never had it refuse to even allow me to ssh in before!

Hope someone has an idea...

Discy