I might suggest trying the following settings. This is a post from a user who figured out how to get some of the streaming features in a Blu-Ray product through the Airport Express settings.
I've gotten it semi-connected directly to my Airport Express - Mac Address, IP Address, Subnet, Gateway all check. But then Gateway Ping has an X. I don't see any settings in the Airport Express Control Panel for Gateway. Also, the main router is an Airport Extreme. The Express was used for AirTunes, but since it's right by the TV, I thought I'd take a shot.
Any suggestions would be appreciated.