Make sure to disable comparators & ECCP module. Using HIGH /LOW commands disables all analog (generally) for you. PICs default to Analog inputs and you have to be sure to turn it all off to get digital to work. And it makes sense too, analog inputs are incapable of causing any "unintended" actions downstream, like shorting something out or causing a machine to suddenly start running on power up. It is for THAT reason you should set your port states prior to assigning TRIS to outputs.