The nomad was working prior to having this problem. No network changes have been made and the only thing I think has changed is that I upgraded my MacBook Air to Mountain Lion. I use a Linksys router, not one supplied by Comcast >> Netgear wireless router>devices. I can ping everything on my network and disabling the firewalls do make a difference. I have 3 solid blue lights on the nomad.
What message do you get, at what point?
Upgrading an OS is very likely the cause of files not being accessed by the nomad app- or the wrong files being accessed.
IAE, I believe that it'd be worthwhile to again delete those files referenced earlier. Make sure they're in the Trash, and then empty it.