Yes, I am still having trouble booking companion passes. I have 41 reservations to book, but my crazy error message persists into the new year.
My problems documented here:
http://www.flyertalk.com/forum/south...r-message.html
Have you had a companion pass for many years? My theory is that a buffer for storing companions from prior years is full and it appears to the system that I have made more than 3 "changes" to a companion (even though my designee has been my wife forever).
GRRRR!