audio.dispose does not work in windows 7

I am having a problem with this code:
[lua]backgroundMusic = audio.loadSound( “sound/menu.wav” )
audio.play( backgroundMusic , {loops=-1} )

audio.dispose( backgroundMusic )
backgroundMusic = nil[/lua]

My problem is that the dispose command does not work

I have the dispose command and backgroundMusic = nil in an event listener that take care of moving from one page to another using the director class.

I added a print() in front and after the command to make sure it’s running. No errors are shown in the simulator terminal and both print() calls shows up fine.

I am using windows 7 and version 2.0.0 build 2011.288 [import]uid: 35997 topic_id: 6973 reply_id: 306973[/import]

audio.stop first? [import]uid: 8872 topic_id: 6973 reply_id: 25345[/import]