Quicktime 5 was released yesterday (April 23). There are
some compatibility issues between QT5 authoring components
and Sonic Foundry products (the crashes on render, as we
saw while testing QT5 beta, are gone BUT you may not be
able to successfully render to all formats in Vegas,
VideoFactory, etc).

You are encouraged to hold off on installation of QT5 if
you want to render to QT formats using SF products. We are
testing the release version of Quicktime 5 now and will
have more news soon.

Quicktime 4 works fine, and as of this writing it is still
possible to download QT4 from www.quicktime.com should you
experience render problems.