Perhaps this particular file has become corrupted (do not ask me why)? Could you try to make a new blank project with the same resolution and copy and paste the slides to that project, not all at once so that you could find eventually the guilty slide (or objects). This workflow has me helped out quite a lot of times, so I'm not looking to long for the cause but immediately start copying to a new project.
Hopes it helps,
Are you still facing the issue?? Will it be possible to send across the two files mentioned in the you second screenshot? you could send the file at: maanand <at the rate of> adobe dot com.