cross frame bgcolor change with FF

I have a page with four frames. I am trying to change the background color of the frame named "upper" based on a hidden form id value whenever a page in the "main" frame loads. I have gotten this to work in IE7 but can't get it to work in FF3.

This works in IE:

if (parent.main) {

if (document.nodeForm.classification_id.value == "C")

parent.upper.document.body.style.backgroundColor = "#33FFFF";

else if (document.nodeForm.classification_id.value == "S")

parent.upper.document.body.style.backgroundColor = "#FF0000";

else

parent.upper.document.body.style.backgroundColor = "#CCCCCC";

}


I have also attached a small zip file that contains all the files I'm working with.
Any help would be greatly appreciated!