Autocad Mechanical 2008 BUG

We are running AutoCAD Mechanical 2008 with service pack 1 installed.
We opened 2 off 3D drawings (it can be any 2) and we copy a 3D object from 1
drawing to clipboard while in ‘Realistic visual style’ mode using the
“Copy with Base point” command under the edit pull down. We then pasted it
to other 3D drawing (also in ‘Realistic visual style’ mode). The problem we
have is, when we paste it into the 2nd drawing the object disappears. If you
then set the drawing to 2D wire frame view, you can see the object, but if you
turn it back to ‘Realistic visual style’ mode it disappears again. The only
way we can get it to stay in ‘Realistic visual style’ mode is to save the
drawing, close it and re-open the drawing. If we open them on the same machines
using just plain AutoCAD 2008, we don't have the problem.

The PC’s we have tried it on are -
Dell Optiplex 620 with a ATI X600 video card
Dell Optiplex 620 with a ATI X1300pro video card
Dell Optiplex 745 with a ATI X1300pro video card

All with the latest drivers installed. 
Have searched the net for people the same or similar problems, but could not
find any.