I was having the same problem, I think, after putting in the building shells and zoning in the design development wizard I was getting an error when moving to detailed mode, this would happen after just opening the program and not actually making any edits that could cause a problem. This would happen after closing the program and seemed to be independent of my building shells, I tried deleting different combinations of generated shells to see if 1 or 2 shells was causing the problem. I found that things would work after making a new copy of the file using 'Save As.' I never did really figure out what was wrong, and would be interested if anyone else has had this problem, but at least it works now.
I was having the same problem, I think, after putting in the building shells and zoning in the design development wizard I was getting an error when moving to detailed mode, this would happen after just opening the program and not actually making any edits that could cause a problem. This would happen after closing the program and seemed to be independent of my building shells, I tried deleting different combinations of generated shells to see if 1 or 2 shells was causing the problem. I found that things would work after making a new copy of the file using 'Save As.' I never did really figure out what was wrong, and would be interested if anyone else has had this problem, but at least it works now.
Richard Auffermann