This is wierd, because the green dot is indicating that the port is forwarded correctly, and accepting incoming connections. If it's green, everything is working alright. If it's a yellow warning sign, it might work, but it haven't got any connections so far. Red, no connections accepted.
There's a protocol called uPnP (Universal Plug and Play) which "talks" to your firewall, and automatically allows incoming connections from the port specified. If your firewall has uPnP support, I strongly recommend this. You can set uTorrent to use uPnP in it's Settings-window, make sure it's ticked and try again.
If you don't like uPnP, you can always map a port (like 48880) to your network IP inside your router/firewall, more information about that on the link Mike gave you above. If you're not going to use the 48880 port, don't forget to change it in the uTorrent-settings as well (I always do this mistake). Every port will not work, for example is 80 already used by HTTP, the normal connection to the internet. I recommend you to use 20000+.
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