Have another look at the web page of your Edimax & look around the different sections. See if you can find an option for UPnP or Universal Plug & Play. If you can see such an option, make sure it's turned on. I just looked at the above link & your device does have UPnP. Click on advanced & you will see UPnP at the top of the list. Click on it. This is the alternative to forwarding a port. Make sure it's set to UPnP & is enabled. Have a look at the link Wondering Why gave you to see where Advanced & UPnP is.
Then open LW & go to LW's menu bar, Tools>Options>Advanced>Firewalls & tick UPnP. Save settings.

For this to work, you'll need to restart LW.
You might need to reboot your router also. Make sure you saved the settings in your Edimax.

By the way, setting your device up for UPnP is Much Much easier than port forwarding. It's not confusing I promise. Just look at the images in that link to see where everything is.