what may be causing letterboxing in this video?
 

i can't embed the flash here, but you can see the video at my blog:

http://www.joshgirls.com/news/?p=293

there are black lines to the left & right sides of the video, suggesting the video is not as wide as the render rate.

the source was a 720 x 480 avi, compressed to a 540 x 360 FLV file. when i play the FLV file with VLC player, there is no letterboxing, so i think it may be the JW player doing this.

any ideas on the cause & solution?

Thanks.