It really scared the hell out of me when I read this post. You are the foremost spokesman for Sinar backs and to hear you are in a jam with their software is frightening. Hope you get this resolved soon. Good luck.
At this stage I really don't know if it's Sinar software at all. I know that it worked until a few days ago, and again yesterday after I reinstalled 10.5.6.
However the reinstalled OSX was missing 10 updates, and I installed those later.
So it makes sense that it is a recent OSX update which is causing a problem. I might have to reinstall my OSX (again) and add updates one by one until I break eXposure, and then reinstall my OSX again and avoid that update.
On the other hand, if someone is using the same conbination of OSX and eXposure as I am, with latest OSX updates, and it works, then it might be something else.
So I am hoping to hear from someone using the same setup to see if it works for them.