Cisco linksys WAG54G2-UK "limited connectivity" error

Trying to setup a cisco linksys WAG54G2-UK for ADSL. Failing at the first step so far! Connected a Fujitsu-Siemens Amilo L1300 laptop by ethernet cable, get a "limited connectivity" problem. Connected another laptop, this time vista, get same problem.
I didnt check on the XP laptop whether an IP was assigned, would it just be 0.0.0.0 otherwise?
on vista ipconfig looks very different, for IPv4 it gave an IP address but it wasnt a 192.168 local one and I had no paper on me so didn't write down what it said.
Its not at my house so just want some ideas before I go round again as I'll probably spend a while there.

Next steps I was going to try are
-disabling firewalls and antivirus software, though I can't imagine this will make much difference
-booting from Ubuntu USB/live CD and seeing what happens
-taking round a known working ethernet cable
-take round another ADSL router! then i can bring this dodgy cisco linksys one home and do some proper testing

Thanks for reading, any suggestions much appreciated,
Dan Gent