[Mike Gerber]

"i think, it's because of the internal parking brake hold,"

Excuse the question, but you don't have the parking brake applied, do you?

If not, there should be 2 threaded holes in the hub of the rotor. Thread 2 corresponding bolts in to those 2 holes and lever the rotor off. If it's rusted to the hub, it will come off with a popping sound. (I believe the threads are M8 X 1.25 thread pitch.)

Mike