the PFC unit you have is correct, there are two versions of the apexi PFC for R33 Skyline
RB25 and ECR33 model codes - both work fine and will no issues, RB25 is first generation, ECR33 unit code is 2nd generation
it sounds like the PFC you have, has a fault with it, or something is wrong with your car
I would remove the PFC, put your stock ecu back in, confirm the car works and runs, starts OK
then if it does, reinstall the PFC and turn the car to ON, but dont start it, the hand controller should boot up and be normal (no clicking etc)
if its clicking, the PFC is damaged or your wiring is mangled (check if car is OK with stock ecu)