Check to see if there are actions on the last frame. It would look like a lowercase "a" on the timeline frame. If so, click on that frame and open your actions window. There may be this command: stop();
If there is, delete it. Because by default, the SWF should loop infinitely, unless they told it not to.
Thank you, but the swf is produced from Camtasia, a screen-capture program, and it doesn't have the same timeline as Flash - no Actions as far as I know.
It seems to be automatically produced with, perhaps, a 'stop' action on the last frame.