Dropdown menu items showing BEHIND the slider images

Hi,
The dropdown menu items are showing behind the slider image. This is a problem! How can I fix it?? I tried adding

#header .container {
z-index:3;
}

but that didn't work...
please help! thx.

Anyone? this is really a big problem as I see it... there has to be a way to fix it, please?

yay! SMThemes gave me the solution by email:
open the file "syle.css" and change value of the following item:

#mainmenu-container{
z-index:18;
}

It worked. Phew!

I did not have this "z-index:" in my mainmenu-container, but I added it and it worked. However.. it works ONLY for the home page. When I go to inner pages, it does NOT work!! WHERE else do I have to add this so that it works??
I have the SunnyBeach theme.
thanks.