For some reason the fscommand(“exec”,”some_app.app”); does not work when you publish a mac projector through flash CS5. the fscommand(“exec”,”some_exe.exe”); works fine when you publish a windows projector through flash CS5. The work around for mac which i came to know is:

navigateToURL (
   new URLRequest(
      "file:///Volumes/Name of Disc/your pdf file.pdf"), "_blank"
   );

this would not open in a browser window but open the pdf in acrobat. check out this forum on adobe’s website: http://forums.adobe.com/thread/790499?decorator=print&displayFullThread=true