I just did some searching and I found this:

http://forum.daz3d.com/viewtopic.php?t=169070

And, it worked for me!

Apparently, the error can come from saving on exit as opposed to saving, then exiting.  If you add a dot z (example: file.car.z) to your file name, then open the file with something like 7-Zip (I used Winrar) it will inflate the file and then you can open that file.

It worked for me.  Hopefully anyone else who runs into problem will be able to find this little trick useful.

Literally saved me days of work.