am going crazy with this.

I have a presentation in Keynote '09, version 5.05 (942) and am trying to export it to powerpoint 2007. When I try to open the presentation, I get an error message saying "Power Point was unable to display some of the texts, images, or objects on slides in the file (name), because they have become corrupted. Affected slides have been replaced by blank slides in the presentation and it is not possible to recover the lost information, To ensure that the file can be opened in previous versions of Power Point, use the Save As command (File menu) and save the file with either the same or a new name."

Anybody else have this problem and know how to fix it?