Hi Howittm, welcome to the forums
This error is sometimes associated with the dynamic allocation of IP (DHCP) on vista where the new network system is incompatible with older routers, you could try setting a manual unused IP from the range that the router is set to issue and see if this helps. if you find that this helps have a look at the Article
Here which will disable one of the new features of vista .
I would also try to connect directly (wired) to the router if possible to eliminate a basic network misconfig.