Network priting

Try to help my wifes boss who has the following set up:

Main pc (running Vista Business) connected to the internet with a ethernet
cable in to a BT hub, this hub sends out a signal which 2 other pc`s with are
running XP.

On one of these two pc`s is connected a Brother printer, this is conected as
is asked for by a network cable, on the pc ot is connected to it prints fine,
we need to be able to access it also from the machine running Vista.

In Vista when you install a printer the printer in question cannot be seen
in a search or even by putting in its IP address, all pc`s have file and
printer sharing turned on.

I have also tried to connect to the printer was all firewall disabled, no
luck here.

Checked the the settings on the hub, all pc`s have full access to the system.

Regards

Ray