There is a recent update for the DPS plugins which you should install if you have not done so already.
The bad news is that the save/save as issue is a known bug for Mac users and is under investigation. I believe the current wisdom is to save IDML when that happens so that you don't lose your work (try File > Export and change the type to IDML). You should then be able to open the .idml and continue editing, and with any luck be able to save that as .indd.
