Microsoft KB article 2543421 is now released and describes the following Microsoft Office PowerPoint 2003 issues that are fixed in the PowerPoint 2003 hotfix package:
When you open presentations that contain layouts with a background images may cause an error when they are opened in PowerPoint 2003. When the error occurs, you receive a message that states that some contents (text, images, or objects) have corrupted.
The specific content lost will be what is specified in the layout, not the actual slide content itself. Items that were removed will display a blank box or a box that contains "cleansed."
A supported hotfix is available from Microsoft here.