>Can you post a simple repro ?

After verification, a conflict was responsible for the failure.

<div class="IFrameContainer" id="IFrameContainer">
</div>

cHtmlFromIFrameTransaction=''

function InitializeIFrameContainer()
{
   loDiv=document.getElementById("IFrameContainer")
   loDiv.innerHTML=''
   loDiv.insertAdjacentHTML('afterbegin',cHtmlFromIFrameTransaction)
}

Basically, the above is in the parent window. Then, a child window initializes cHtmlFromIFrameTransaction and calls the function.

parent.cHtmlFromIFrameTransaction="Html here"
parent.InitializeIFrameContainer()