i get the same error, its hard to say whats wrong without seeing your setup in cocoon. Im not so familiar with cocoon that i could take any guesses whats wrong.
My only tip is, try exporting with XDK.
These are the settings i use and everything works fine
make sure your files are at the specified folder
you will need the device plugin but the media plugin only if you have sound.
make sure you select Cordova 3.5 and the correct AppID
everytime you upload a new apk to playstore you will have to increase 'App Version Code' by at least 1
then build with the second option, "Android"
hope that helps!