Battery’s status is “Not Charging”

Dear Friends,

I got a gift from one of my friend "Macboo4.1" OS Mac OSX10.6.8 (10K549). When ever i connect the Power Adapter. It Shows in the Menu bar "Battery’s status is “Not Charging”. and the battery will never get charged. please help me to charge my battery. The Status shows that the battery condition is good.

Please help me to over come this issue or solve my issue.