[c-prog] Abstract class

[glogic20]

Hi all 
I just have a question on abstract classes. I have created a class using 
multiple inheritance
class ExitListenerAA : public FrameListener,  public OIS::MouseListener, public 
OIS::KeyListener
{
public:
    ExitListenerAA(OIS::Keyboard *keyboard): mKeyboard(keyboard)

//code
}
In my main code i am creating as follows

ExitListenerAA *mListener;


mListener = new ExitListenerAA(mKeyboard);

On this line i get an error 
Error   1       error C2259: 'ExitListenerAA' : cannot instantiate abstract 
class

Im just abit confused on how this error comes about. Any help would be great 
cheers
G