Well, here's a duplicate of what I said:
After moving the larger file, did you delete it from your presentation and then
re-insert it from its new location? When you play the presentation it might
take awhile to load that file. Are you waiting an adequate period of time?
Have you tried the tips at
http://www.echosvoice.com/tshoot_video2.htm - - especially #1? Try turning
hardware acceleration off.
It looks like the first copy of mplay32.exe was installed with Service Pack 2
for Windows. I haven't ventured into Service Pack 2 on my main system, but I do
see C:\Windows\I386\mplay32.exe on my laptop that has been upgraded. I suspect
that these are cached upgrade files, but I don't know that for sure.
Regarding the smaller WMA files that don't play across files, check to make sure
that they aren't set to stop playing after current slide or on mouse click. If
you want them to play twice, even if the slide is advanced, you'll need to set
them to play across multiple slides.