Having Norton FW activated will help protect you. You shouldn't run without a firewall.

Make sure your Linksys device has UPnP activated. See example here as yours should be similar: Linksys UPnP setting (click on link)

Then go to LW's menu bar, Tools>Options>Advanced>Firewalls & make sure UPnP is checked. Once all that's done you should be fine.

At least, I'm guessing your quest device is a simple modem right? If it's a router then please supply model number.