Thanks everybody.
Well, I upgraded to Flash CS3 today and attempted to produce content shown on the tutorial DVD.
All appeared to be fairly straightforward, but when I tried to test the finished swf file, it plays for the first two seconds and then just freezes! Attempted to do the same with another video (all captured as Quicktime Blackmagic 10-bit files from FCP and then converted using the Flash Video CS3 encoder), but the same thing occurs.
I have ensured that my frame rate matches, but other than that don’t know what I should be looking out for?
Thanks for the tip on mediabatch, I will check this out as well.