1996 Plymouth Voyager Parking Brake system

Brakes problem
1996 Plymouth Voyager 4 cyl Two Wheel Drive Automatic

On My 1996 Plymouth Voyager, my husband has replace the whole parking brake cable system, We can not get the cable to stay on the pedal. He attaches the cable to the pedal, the cable comes off when the pedal is depressed. He slides the cable in to the hole in the pully and squeezes the tab so that the cable is pinched in, and then he hooks it up to the rest of the system. The rest of the system is fine, just that the cable is coming off the pedal are we doing something wrong or missing something. Thank you