Hi awalla -
Make sure you have removed the emergency brake cable from the actuating lever on the rear of the brake.
Then, you can use a screwdriver or (preferably) a brake adjusting spoon to back the emergency brake off a few turns. You can check to see if the brake is binding by turning it back and forth - the rotor should turn without any brake interference - only the driveline drag.
If all of this seems ok, then you are back to hitting the face of the rotor, between the lug studs, with a hammer. I use a 3lb sledge for this.
Hit it, wiggle it, hit it , wiggle it etc. It WILL eventually come off - some just take more persuasion than others....
If you are not fighting the emergency brake pad material, then all you are fighting is rust between the mounting pad and the rotor.
Some folks have had the emergency brake come apart inside the rotors "drum" - you should be able to see if there is any abnormalities like that by inspecting the brake from the half-shaft side of the brake.
best regards -
mqqn