FAB 3000 is not meant specifically to run in an Apple MAC environment. If your using a product such as Parallels, Virtual Box (or similar) than I would recommend that you save directly into the Windows path enviroment (i.e C:\Users\MyDocuments\MyFolderWithGerbersDrills\). Then you should be able to easily transfer those files to your MAC environment.
I did try that and it worked perfectly! No issues other than that working with Parallels. It's doing what it's supposed to do with no systems upset.
Have you ever encountered a good export with "success" showing all of the files that were exported but then they are not appearing in the folder that you saved to? Even when choosing a second export to the empty folder it asks if overwriting is ok.