My Bernina walking foot goes on right away about half the time. The other half of the time, I have to wrestle with it.
I got mine when I was doing my very first quilt and was definitely "underwhelmed" by the results because it didn't "walk". I took it back to my dealer and they had me put it on the floor model of my machine while they watched. I'd forgotten to put the fork thingy around the needle arm. Duh! They were very nice about it but I felt like a complete idiot.
I couldn't figure out what was wrong from your pictures but don't give up. Bernina dealers are wonderful and will help you.