That's good about your test result. That means your router uses UPnP tecnology.

The download preferences are those called download.dat & bak in the incomplete folder (ie:different files in different location.) So deleting the main LW preferences folder will not affect them at all. But LW must be closed when you delete the Prefs folder. Follow the instructions in the link (there's an easy image to follow at bottom of that page) & you'll find it quick & easy to do.