[CentOS] Firefox and xmms issue

I'm almost certain that I had this working before, but it seems to have quit.

I used to be able to go to a web page, click on a .wav file and have it automatically load into xmms and play, and that was all there was to it.

Today, I click on a wav file and it opens another empty Firefox window, then loads xmms and sits there until I hit the play button on xmms. Worse, if I close xmms and the empty Firefox window, then click on another wav file in the original Firefox window, it goes through the same process but then when I hit play I'm listening to the first wav file again.

So... what happened?