Passat (B6) :: Rear Wheels Splayed Out

Last week, I noticed that my rear wheels were splayed out. That is, the bottoms of the wheels were further from the center of the car than the tops of the wheels. I drove to the dealership (abut 2 miles from where I was when I noticed the issue) and discovered that the tires had worn through the steel cords on the inside edges.

They did an alignment and put on two new tires and I was on my way (3 1/2 hours later). They could not tell me what had gone so terribly wrong to cause this, but they also told me that they could not get the passenger side rear wheel aligned because of the cam bolt. Apparently it is quite worn. They said it was a 4-5 hour job replacing this bolt. Does this seem reasonable?

Since this episode, I have noticed that my car is really jumpy when I am turning left. Mostly on long turns like ramps and curves in the road. By "jumpy" I mean that the car seems to jerk around side to side during the turn. I worry about losing control.

I can't tell if the problem is caused by the front or rear wheels, but I don't feel anything strange in the steering wheel. In my mind, I feel that it is the rear wheels, but that may just be because of the recent work I had done. What might be causing this?