Create new ActionScript project... how can I set a null SDK to something useful?

Hi,

I'm trying to create a new ActionScript project in Flash Builder... Simple, you say, "File - New ActionScript Project".

Right.

But when I do that, I get:

And that then gives this:

So...

Obviously, I have something that is badly misconfigured somewhere. Hopefully something _REALLY_SIMPLE_ but I don't know what it is!

Anybody?

Please?

G