layers and iframes

["omegaredmarine" <webforumsuser@xxxxxxxxxxxxxx>]

i am a novice at web design and i am working on a site that uses pop up menu 
one in each layer i created.  i have two layers and an iframe.  i have set it 
up so that the links in the pop ups show up in the iframe.  and when the iframe 
loads the page my menus work fine. but if you click on a link in the iframe for 
a file... for example. one of my pages has a link to an excel document.  and 
when it opens up it opens up in the iframe like i want it but then the pop up 
menus get cut off .. why is it doing this.. i tried changing the z value of the 
two layers to keep them on top but it doesn't work.. and i tried to make a z 
value for the iframe to make it towards the bottom but its doesn't work or im 
not doing it properly..