Animation suddenly stops

hi guys, i need your help…

We are doing a 5-6 min. (30 FPS) interactive animation…the only AS are goto, stop,
play, fs command (fullscreen, scale, quit). All of the sounds’ sync is Event. Ok the problem is,
**when I test the movie, one of the last scenes suddenly stops but when I test that scene, it plays normally.

**Here are the steps that I’ve done so far:

  • I’ve checked the scene for uneccessary AS such as stop - nop, there were no AS stop
  • I’ve restarted my PC (hoping this will do it) - nop, no effect
  • I’ve deleted that scene, and recreated it - still no effect
  • I’ve removed all the file’s AS, then save & exit, then re-open the program, recreated
    all AS again - no effect
  • removed the .wav sounds, tested the movie (to see if audio has the problem) - NE
  • removed the images, tested the movie (to see if images/objects (all are .png(s) &
    .jpeg(s)are the problem) - NE
  • copied, pasted all scene in a new document - NE
  • reinstalled the program - NE
  • mixed up the scene’s layers, keyframes, (i’ve also reduced the frames before the frame
    where the error occurs) - NE
  • changed the object/image/symbol; the style of animation, the sound file - NE
  • changed the sync to STREAM/START - NE
  • tested on 5-6 PCs (with diff. specs) - NE
  • changed the FPS to 31,32,40 - NE

**add info: **my friend & I did this 50/50 (same format) and combined it to a full length
animation. This is the 3rd time it happened (3 out of 20 animations), still we haven’t
figured it out. On those 3 cursed animation, all we did was recreated (as whole document)
each of them individually. It worked, but we’re not sure (what if the error strikes back in
the next animations), we have no choice but to redo it all over again.

Hoping for your holy advice, masters of Flash