[ubuntu] can't access my home network anymore

Hi,
I have been at this for some time and been through many posts without luck, thus turning to the experts for help....
I have previously setup a home network as follows:
desktop - wireless (the server - kinda) ubuntu 12.10
laptop - wireless ubuntu 12.10
netbook - wireless ubuntu 11.10
all runnung through a virgin media supplied router.
Note that I have recently upgraded the desktop and laptop to 12.10.
The netbook can still access the desktop, but even though some traces of the working network exists (icons) I am not able to connect between the laptop and desktop.

In my nautilus bookmarks I click on the LAPTOP icon.
The error message on the desktop side trying to connect to laptop:
Could not display "smb://192.168.0.4/"
Error: Failed to retrieve share list from server
Please select another viewer and try again

!!!!!!Note the correct address is 192.168.0.5, the one in the message!!!!!

If I try and connect from the laptop the error is:
Unable to mount location
HTTP Error: Cannot resolve proxy hostname ()

I have tried changing the order of host etc in smb.conf file etc. and this does not work.

Your help will be much appreciated.

Jacques