network problem

Hi can anbody help me i have hit a problem.I have my dreambox set up with home plugs do these cause problems? When i go into communication set up the ip is et fot the dreambox net mask is 255.255.255.0 and the nameserver and gateway are set to my home hub.If i do a test it passes the bottom two but not the top two ip and netmask.If i us dcc it connects ok and my homehub is showing it connected.Has anybody had this happen to them?
Thank you