Need to play a runtime shared sound in AS3

Question

I am having a hard time playing a sound that was imported from a shared library of a second SWF file.
On the shared library FLA, I have my sound's linkage properties set to:
Linkage Identifier: MySound
Export for Actionscript
Export in Frame 1
export for runtime sharing
The Linkage Identifier is a simple identifier (MySound) with no .wav at the end, and no spaces.
On the destination fla, I went to File -> Import -> Open External Library.
I browsed for the shared library FLA, clicked it, and dragged the shared sound into the destination FLA library.
On the destination FLA, I have the sounds linkage properties set to:
Import for Runtime Sharing
Sounds.swf is in the URL field.
Now, for the Code that plays the sound:
var mySound:MySound = new MySound();
var myChannel:SoundChannel = new SoundChannel();
myChannel = mySound.play();
Flash gives me an error that says:
ArgumentError: Error #2068: Invalid sound.
    at flash.media::Sound/play()
    at Player_fla::MainTimeline/frame1()
What am I doing wrong?  Please help me.

Answer 1

I'm curious, what *should* the crossdomain file say, and
where should it be. I am looking at it now, and it says:
<cross-domain-policy>
<allow-access-from domain="*.domain.ca" />
<site-control
permitted-cross-domain-policies="master-only" />
</cross-domain-policy>
and it is at
http://video.domain.ca/crossdomain.xml
Is this right, or did we miss something?
As a side note...I'm wondering if somewhere in my code, I am
calling this wrong (this is the first time I have tried doing
this). My code is attached.
Thanks!