getURL problem

I have a standalone projector running off CD. When my client click on a button with this code

on (release){
getURL(“http://www.bdo.ca”,"_blank");
}

to open the web browser to a webpage. The web browser opens a new window on top of the Flash window (fullscreen) as it should. But if the client goes back to the Flash piece leaving the browser open (so the web browser now goes underneather the Flash window) and click on the same button again, my client claims another new web browser window opens up but it is hidden under the Flash window. They are using IE6 on Windows XP pro. What would cause that?

TIA