You may need to 'turn on' your wireless adapter as when it's not required it's taking power from the battery.
The wireless radio circuit can be turned on / off by pressing (Function) Fn and F1 together. By default it is switched off. There is a bit of an problem on the early models as the wifi light on the front of the webbook does not get turned on when the wireless is activated, making it a little tricky to tell whether wireless is on or off.
Our laptop is the same.
Hope this helps.