Cannot connect with DNS Server 192.168.0.1

> Can someone please help me reslove this problem?
>
> I administer a small network based at a sports club. We have a BT badged
> 2Wire Gateway Router, which provides our connectivity via DSL. The main
> (HP
> Media Center) office PC runs Xp and connects to the router wirelessly (set
> up
> by previous administrator) This PC is hard wired to the office HP wireless
> printer.
> The Assistant Manager has a IBM X41 running XP which is also wirelessly
> linked to the gateway (again set up by previous administrator)
> THE PROBLEM:
> The manager has purchased a Sony Vaio running Vista Business and although
> I
> have manager to get it to connect to the gateway - I am unable to get a
> connection to the Internet unless I connect directly to the gateway with
> an
> ethernet cable. The error message I get when I run windows diagnostics
> is,
> 'Cannot connect with DNS Server 192.168.0.1
> I have tried sysedit to change the DHCP Broadcast Flag value to
> 1(disabled)
> Although I am pleased to have all the functionality via the ethernet
> cable -
> the manager wants to work via Wireless so she can move around the club to
> work.
>
> --
> Frankie