In Flash, all of the animation is done at runtime, not during authoring. This means that a blur, for instance, is done when the user is looking at the movie. This is completely different from the way that video is played on a computer. All of the animation workload is on the user's processor.
If you have a normal bitmap image that you are blurring with a blur filter and then animating that bitmap on the timeline in a tween, then you are giving the processor a lot of work to do. If you import a blurred bitmap and animate that, the processor has much less work to do.
That may or may not describe the problem that you are seeing.
I have no idea what the problem is with the sound files. Can you post one of the sound files so that someone could take a look at it?
Okay, I'll try using pre-blurred images (from PS) and then tweening them into the unblurred versions
Here's the original(ish) version of the background track that I'm using... was originally in .wav but converted to .ogg and now .mp3:
(sorry about the crappy provider, but I don't really want to have to register another account on some service I'm only going to use once)
I just tried your sound file. I imported it into Flash CS6 and it played just fine. How are you importing the sound file? Are you using Mac or Windows?
Using windows and Professional CS5.5. (also tried to import the .ogg on a different computer with just CS5, but that didn't work either)