The hell? Such a vague error message!
All you really needed to say is that the width of the image must be even, as (not so clearly) stated by the documentation.
Once that's worked out you should be getting faces again.
public FaceDetector (int width, int height, int maxFaces)
Creates a FaceDetector, configured with the size of the images to be analysed and the maximum number of faces that can be detected. These parameters cannot be changed once the object is constructed. Note that the width of the image must be even.
Parameters
width
the width of the imageheight
the height of the imagemaxFaces
the maximum number of faces to identify
It's all about getting the right face.
