Before you can start reading counts from the encoders, you have to call Start() on them first. It looks like you've defined a function that does this for both of your encoders, but that function is never being called. You should call your EncoderInit() function wherever you'd like to start taking measurements, perhaps in RobotInit() or in your constructor.
Code:
void RobotInit()
{
// .. Existing initialization code..
EncoderInit();
}