OS 10.4 - Updating problem

hi all.

I recently took my Powerbook G4 to the apple store in London for them to look at my machine. They re-installed OS-X and plugged it into their network via ethernet cable to update the machine, the apple "genius" ran a script in terminal, which i do not know what it was and then updates occured.

I took it home, and a few weeks later tried to update the machine myself, however i get an error saying that i am not connected to a network, when i am connected to my home network wirelessly. It also does not work on any other networks i try, at friends houses.

It searches and then i get the error saying software update cant find the update server, make sure you are connected to the internet and try again. I then run network diagnostic and it ses the server connection fails but all else is ok!!

ANY HELP WOULD BE GREATFUL!...

thanks.