Yeah - I have a senior friend who also send/receives a bajillion of these silly PowerPoint "inspirational" thingies with music. NeoOffice doesn't import those files very well - and FYI, neither does Keynote. NeoOffice will play the sound only on the first slide, but not through the rest of the slideshow.
You could try the NeoOffice "Trinity" forums
to see if anyone has fixed this.
Also - are you up-to-date on your NeoOffice patches