First, Check that you've got the latest updates for both Archicad (Help>Check for updates) and Artlantis
http://www.artlantis.com/download/ .
Then, check that you're saving from the 3D view in Perspective mode, not a Parallell projection. If that's not the problem, I'd guess some object is screwing up you file. Try using the Filter elements in 3D command, filter out all objects, and save/open in Artlantis again. Then filter out all windows, then all doors etc.
You should also check that you have full read/write permissions to the file (on the Mac, in Finder, select it and use File>Get Info.
AC4.1-AC26SWE; MacOS13.5.1; MP5,1+MBP16,1