Vista - Invalid IP with internet via nokia/bluetooth

I connect to the net via my phone's 3G connection and bluetooth on my laptop
and messenger tells me that my IP is invalid. I have tried all that my
knowledge will allow me, plus following a few other instructions I've found
on the net (deleting reg settings, clean install), so I guess that it is just
my IP settings suck So anyone tell me how I can either:

a) disable this action as i know I'm connected to the internet

or

b) change IP settings to allow me to connect?

I want to use the actual prog rather than webmessenger (which works fine :s
) as I want use audio chat features.