Wdtv Live +Airport extreme & express

Hi. I have the Wdtv Live connected to the Airport express, which is set up as an extension to the Airport extreme network.
When I try to set the Wdtv up, the IP adress of the Airport express is accepted, but neither the DNS:s of the express or extreme.
What shall I do?

Hi there,

Have you tried setting up the network manually to see if this helps connect the unit?