Thank you for your responses. My machine is a Pfaff Hobby 1142.
I had actually purchased one of the walking feet from the dealer. Unfortunately that was the one that came bent out of the box. I don't blame the dealer. The box looked like it might have been opened before so I think someone returned it without explaining what the problem was and the dealer resold it. I would have returned it myself but I threw away the box and receipt right after buying but didn't actually use the foot until much later.
All of the feet I've bought have been generic. I can't seem to find a Pfaff walking foot. Maybe they don't make them since the walking foot mechanism is integrated with most of the Pfaff machines. I guess I'll try the dealer again and see if the bent foot was just an anomaly.