I've came across this issue a lot on forums and help groups "My drop down menu is hidden by Flash/Banner/Other-Element" First a few principles should be cleared to understand how to get it fixed.

• The Flash movie must have the wmode set to opaque. This will prevent the Flash movie from playing in the topmost layer and allow you to adjust the layering of the movie within other layers of the HTML document.
• The menu container have to be positioned with CSS using (relative)
• The Flash movie container must have a z-index value less than the menu container

So the CSS for the menu container should be like :

#menu-container {
         position:relative;
         z-index:100;
}

and the Flash movie should be :

 wmode=opaque 

This should place the drop down menu in-front of the Flash movie

Hope this saves anyone from frustration! Have a nice day :)