I have been having the following error message pop up on me on several different machines all running Mac OS X v.10.2.5 and Illustrator 10.0.3 only over the past couple of days.
"Acrobat PDF File Format is having difficulties. Object level badly formatted."
The file save seems to get almost to the end when the message appears and consequently nothing is saved.
At first I thought that the problem was limited to when I was trying to save files that were being worked on off of a server (XServe, in case anyone was wondering). This was soon proven incorrect as after a few saves the exact same problem appears when saving a file locally.
It seems to take three saves for the problem to appear with ANY file save on three different Macintoshes.
I am have trashed Illustrator preferences, re-intalled the application, trashed "dfont.xx" files and the whole shooten-match. I am also running Font Reserve Client 1.6 (running of the server application) on all machines. In that software's respect I have cleaned cache and preferences on multiple machines, as well.
This seems as this may be a problem from the recent 10.2.5 system update since it was only a few days after that that the problems began--on multiple computers. Why it would take days to manifest itself I cannot say.
I have also posted this message in the Adobe Illustrator Macintosh forums. Somebody, please help!