Conversions
I own two copies of another software called Conversions Plus. It was intended to enable Mac operators to pass off information to PC users. However, it also does translations within similar formats, or pictures to different style pictures. When I tried to open up the compressed files in 6 it gives a similar responce, unsupported. When I try and open it up in version 3, it indicates the compression version had yet to be invented, but does open it up, but will not let me revise to another format. Only solution so far has been to open up in Kodak Imaging which is freeware on many Windows systems and then go on.
Conversions Plus also has an Autocad to different cad software available as about $300-400. I have yet to need such nor have seen it operate.
Wm.