No connection to your local flash debugger when using flex in vista? Showing the message: “Waiting for Flash Player to connect to debugger”? Perhaps your reference to localhost in windows\system32\drivers\etc\hosts has been removed.
Simply add 127.0.0.1 localhost to your hosts file and your debugger can connect.

Costed me over more than 2 hours to find it out, hope you will find this solution faster!