Windows 7 POWERPONT 2010 - when I conver7 to a video, wav files end up in different place

[HCN1979]

I have been creating 40-50 slide slideshows in Powerpoint2010. I have been recording my timings and narration, including wav files for sound effects. This have been found from insert - clip art - audio. Simple things, approx 4 5 secs long. I have then been creating a video from my slideshow in media player. However, I am finding that when I play my new videi, the WAV files do not play in the correct place as rehearsed and saved when I originally recorded timings and narration. Why would this be so? Thanks.