How to insert a DiV in to document

I am trying to insert a Div into  a document this is the code, It works on simple forms but when I put it into the main form i get an error. I think it may be a nesting issue or somthing see sample code below..

'code to add div
               
diva = document.getElementById("test")
divb = document.createElement("div")
document.body.insertBefore(divb,diva.nextSibling)
divE.innerHTML = "<span style=\"color:red\">Test it</span>"

'html

function insertHere
set      divD = document.getElementById("firstDiv")
set      divE = document.createElement("div")
      document.body.insertBefore divE,divD
      divE.innerHTML = "<span style=\'color:red\'>Child E</span>"
Set NodeList = document.getElementsByTagName("div")

end function


<table border='1' cellpadding='0' cellspacing='0' width='25%' height='100%'><tr><td valign='top'>
    <table border='0' cellspacing='1' cellpadding='0' width='100%' height='100%' bgcolor='#f1f1ed'><tr><td valign='top'>
    <div id='masterdiv'>
        <div class='menu' onclick="SwitchMenu('sub1')"><img style='vertical-align: middle' width=20 height=20 src='icons/txtmenu.gif' border=0 hspace=3>Text Folders</div>
            <span class='options' id='sub1'>
             <div id='firstDiv'>
                <div id="childb" class='option' onmouseover="getDiv(this)" onmouseout="this.style.background='#f5f5f5'">
                <a href='http://www.google.com'><img style='vertical-align: middle' width=16 height=16 src='icons/txtfolder.gif' border=0 hspace=3>Text Links</a></div>
   
'=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
'Want to insert div here
'=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

                <div class='option' onmouseover="this.style.background='#D8E4F8'" onmouseout="this.style.background='#f5f5f5'">
                <a href='http://www.industriavirtual.com.br/master.asp?code=webpacks&subcode=basico'><img style='vertical-align: middle' width=16 height=16 src='icons/txtfolder.gif' border=0 hspace=3>Text Links</a></div>
   
                <div class='option' onmouseover="this.style.background='#D8E4F8'" onmouseout="this.style.background='#f5f5f5'">
                <a href='http://www.google.com'><img style='vertical-align: middle' width=16 height=16 src='icons/txtfolder.gif' border=0 hspace=3>Text Links</a></div>
                        </div>
            </span>


etc...