MSO9.DLL error messages

If you receive error messages that mention MSO9.DLL while printing from PowerPoint, try the following:

• Turn off background printing:
• Choose Tools, Options from the menu bar and remove the checkmark next to Background Printing on the Print tab of the Options dialog
• Try printing again.
• Check for corrupted objects in your presentation
• Print half your presentation at a time.
• When you determine which half of the presentation causes an error message, print half of that half, and so on until you've narrowed down the problem to a single slide.
• Delete and re-create the slide (or delete and re-create any charts or other inserted objects on the slide).

Note: You may also receive the same MSO9.DLL messages while saving or exporting slides to JPG/PNG/GIF/WMF image files. The same suggestions apply.

And a few more possibilities from Auntie Echo's Web Dives:
These might be relevant.

See this if you've renamed your My Computer icon
See this if you're getting crashes or out of memory messages while printing/exporting
This one's specific to Word but explains how to replace MSO9.DLL if you suspect your copy is corrupt