I think that part of the problem is that you, Mark, are setting up a router, while Dignan is trying to set up a bridge. I get the impression that you have put the "external" IP address of the DD-WRT system in your normal network, but the clients behind it are in a different network. In general, it's possible to make this work, but it's more complicated. Can you make a connection to those clients from your normal network? My gut tells me no.