Deluge
In Deluge, if I set it to use UPnP, and click "Test Active Port", it says its open, but I have the "No Incoming Connections" error in Deluge.
When I disabled UPnP mode, and clicked "Test Active Port", it fails as expected.
When I forwarded a range of ports to my computer in my router and had Deluge use those, the "No Incoming Connections" error nearly immediately goes away and clicking "Test Active Port" says the port is open. Sticking with this method for now...
Other UPnP programs work fine with my router.
Seems like there's two problems - something with the UPnP port opening and something with the port tester (or maybe its just some side-effect of the UPnP not working correctly). Or maybe there's some quirk about the "No Incoming Connections" error I don't understand. I checked the FAQ and didn't see anything about it mentioned.