Moving #iUngicontactForm from the table to the body tag will fix it.
The problem is that the z-index of an element is inherited from it's parent and it only applies to sibling elements. And as you're using fixed positioning, it's a quick fix.
So instead of something like this:
<body>
<table>
<tr><td>some content..</td></tr>
<tr><td><div id="iUngicontactForm"></div></td></tr>
</table>
</body>
do this:
<body>
<div id="iUngicontactForm"></div>
<table>
<tr><td>some content..</td></tr>
</table>
</body>
