Unity 3.5 - Flash Export

Hello,

Not sure if I'm being stupid, but I can't seem to build my unity game into flash? So, I've made a new project, and all I'm trying to do is to export a build of flash... But nothing happens?!

Okay, so in my build settings, I've selected Flash Player for my platform.. Although it says in brackets its a preview? It also comes up with a notification saying "This is a pre-release version of our flash publishing option".

When I hit Build and Run, it starts to load, but nothing actually builds?

Reasons?