Audio in LMS works inconsistently, depending on computer used

We're in the process of moving to an LMS (a SAAS model). As part of this transition, we did some course modifications, and in addition to global play audio/stop audio controls, we added a pause/resume feature and converted all of our audio to flv.

When we upload the courses to the LMS, the way the audio works is inconsistent. It works perfectly if I access the LMS using my desktop (Windows XP and IE8), and on a laptop that runs Windows Vista and IE7, but won't work on an older laptop (also Windows XP and IE8). On that machine we have to toggle the stop audio/play audio button 3 times before the sound will work, and then when we move to the next page, it doesn't auto play like it is supposed to. Then I tried accessing the LMS using my desktop and Google Chrome, and it works inconsistently.

I'm totally befuddled - I thought two computers using the same operating system and the same browser should have the same results. Does anybody have any ideas for me as to what to try next?

Oh, I also tried using high compression on the audio for the first few pages to reduce teh file size - that didn't help.

Arggggg...why does everything have to be so difficult!!!