Setting levels

I am having a hard time making swf’s on levels visible and unvisible

on the first frame I have this

  onEnterFrame.set._level10

I have put this on my buttons

on (release)
{
getURL(“compass.swf”, “_level1”);
_level10._visible = false;
}

This loads the correct swf but I still see the last swf under it.

Any help would be kind
Thank you
Titoqan