I did a google search and found the following.

http://www.pentaxforums.com/forums/p...ing-error.html

Also checked photo.net and found the following discussions.

http://photo.net/medium-format-photography-forum/00REgo

http://photo.net/medium-format-photography-forum/00A444

I have had my 67II out in the cold but never had it bonk and flash an error warning.

I hope one of these links gives you ideas.