You are off to a good start by paying attention to codecs and
container formats. If you have not already, you might also check the
thread at
http://groups.google.com/group/e-prime/browse_thread/thread/d18aafdc51d79ba9
, which in turn has links to other resources.
You did not say whether you run this under Windows XP, Vista, or
7. AFAIK, PST has still not gotten movies & sound to work reliably
under Windows Vista/7, so if you use those, then it is no wonder that
EP gives you these errors with movies.
-- David McFarlane