If the originating drawing geometry was created in a vertical AutoCAD application (LDD, ADT, etc) even if the objects are "dumbed down", copy/paste will fail most of the time. The drawing objects, even though they are simply geometry, many times have persistent reactors attached. During the copy/paste, the mechanism AutoCAD uses to create the pasted contents will fail due to the fact the creating application for the reactor is not present.
This is one of those types of drawings that I find I must strip all of the xdata from the geometry just so I can use it.