Urgent: Autocomplete css

Urgent: Autocomplete css

I am using jquery autocomplete. Its working fine. Only issues I have is with its display.

Now I have a textbox where users type in the  text. Below the texbox are some other controls such as texbox, dropdownlist etc.

Now when the user start typing in my autocomplte textbox it shows all the suggestions below but it still displays my controls below, i mean my result should be over the controls below and my results box should overlap my controls. Right now it seems my results box is transparent.

Any suggestions. Here is the css that I currently have.
 
.ac_results {
    padding: 0px;
    border: 1px solid black;
    background-color: white;
    overflow: auto;
    z-index: 99999;
   
}






.ac_results ul {
    width: 100%;
    list-style-position: outside;
    list-style: none;
    padding: 0;
    margin: 0;
}





.ac_results li {
    margin: 0px;
    padding: 2px 5px;
    cursor: default;
    display: block;
    /*
    if width will be 100% horizontal scrollbar will apear
    when scroll mode will be used
    */
    /*width: 100%;*/
    font: menu;
    font-size: 12px;
    /*
    it is very important, if line-height not setted or setted
    in relative units scroll will be broken in firefox
    */
    line-height: 16px;
    overflow: hidden;
}

















.ac_loading {
    background: white url('indicator.gif') right center no-repeat;
}

.ac_odd {
    background-color: #eee;
}

.ac_over {
    background-color: #0A246A;
    color: white;
}


 
Also I am using IE6:
can somehow i make it work for ie6 
 
Appreicate help