Error in exicuting my 1st app

i am very new to ionic-2 , now i am trying to run my 1st app but i am getting this error.

ERROR: Unable to add plugins. Perhaps your version of Cordova is too old. Try updating (npm install -g cordova), removing this project folder, and trying again…

I executed this command npm install -g cordova , and also have the latest vesrion of cordova , how to solve this issue .
Thank you .