just a few questions … you may have already explored these, but thought I’d ask:
a) with many editors, you are certain that one is not clobbering the edits of another? i.e. – the slide and note edits have been made and saved “cleanly”, but do not print or display properly
b) if you have a suspect file, and the edits to slides involve text changes, have you dumped the PPT to RTF and had a look? this once helped me collect important text from a fouled-up PPT and start over.
c) what does Adobe PDF think the file contains? render the PPT as a PDF and have a look.
d) the biggest problem I ever had was pushing MS limits with PPT graphics and their autosave and compression features. strange behaviors all round in PPT 2000, and I couldn’t say whether 2003 is still funky in this regard.
I’ll stay tuned to see if you catch that goblin!