Each etransmit has multiple drawings in it. This one in particular has 30 files so converting wouldn't be feasible unless there is a way to automatically convert the fields to text within the etransmit. I don't see that option.
Fields were not introduced into AutoCAD until version 2005. If a user is opening DWG's that use fields in versions before 2005, it is unpredictable how AutoCAD will read those objects. This may be part of the issue they are having if they are using version 2000 or 2002.