ukbobboy01 is on the spot. Although your device has UPnP, not all devices have a good implementation of UPnP. Since there's more than one definition of it (duh), it doesn't always work well. So can you tell us what brand & model of device(s) you're connecting through?

UPnP is a little like beta & vhs or dvd HD where there's 2 or more camps heading in slightly different ways.