Skipped Powerpoint Slides in F4V

I have imported a simple (no annimation, just text and graphics) 7 slide powerpoint (2007 .pptx) presentation with naration into Captivate 5. No problems encountered.

Added my usual flv splash intro at the start and end of the slide deck. Published the project as a F4V file. When I play back the F4V file, one slide runs ahead or behind the audio. Here is what I have done to solve the problem:

1. Updated Captivate 5.

2. Import the slides with the "linked" box check and unchecked each time as a different project.

3. Spilt the slides into 2 separate projects. Both seem to run OK on Adobe Air but one slide runs ahead or behind the audio when I post it on MS Sharepoint.

4. Tried importing it as a Powerpoint 97 file, ppt instead on pptx not change.

5. Tried converting a few slides to f4v and then combining the f4v files into a single project. individual f4v files seem to play OK but when combined into a single F4V file, one slide runs ahead or behind the audio

6. Published the project on a different laptop. Same problems.

Run out of ideas. Help !!