I've replaced the rotors and the brake pads so far, but the brakes continue to pulsate whenever they are applied. The slides on the caliper are not stuck or frozen, but I think they may be the problem. Is there anything that would cause this?
If your vehicle has Antilock brakes remove the fuse for the ABS and see if the problem persists. A faulty sensor may cause the ABS to activate when it is not needed. If the issue is resolved with the fuse removed you must diagnose the ABS system. Two common causes for pulsation even after the rotors are replaced are failing to use a torque wrench to tighten the lugnuts and tweeking the hub. Another more common cause if rust build up on the rotor to hub mating surface. Many rotors have an extra hole between the lug stud holes. I have no idea what it's purpose is but is usually larger than the holes for the stud. rust forms on the hub at this unused hole. When the new rotor is installed the rust causes it to sit a little high. When everything is tightened down the rotor warps.
Check steering and suspension components, often times bad worn steering rack, tie rods or other components in the vicinity will also cause pulsation.
Also, if you still have your old rotors you could check trueness of those to confirm that it's actually the warped rotor that plays part in the pulsation.