Playing MP3

[Michael Kann]

This should be an easy one. It just doesn't seem to work here on Vista -- 4.0.0 build 950.
I want to play a section of an mp3.  This is my script:
on mouseUpset the filename of player 1 to "a.mp3"set the playSelection of player 1 to trueset the startTime of player 1 to 53000set the stopTime of player 1 to 54000play player 1end mouseUp
The sound starts as expected at 53000, but doesn't stop at 54000. How do I get the sound to stop? 
Thanks in advance,
Mike