Help! AJAX call not working from fckplugin.js

Hi,

I've copied the Placeholder plugin and modified it to meet my needs.
It opens a dialog and allows the user to select from a pulldown.
When OK is pressed, the following function is called:

FCKOpens.Add = function( reportId ) {
Ext.get(FCK.EditorDocument.body).load({
url: '/srt/php/get_report.php',
scripts: false,
params: "reportId=" . reportId,
text: "Loading report..."
});
}

This is a function of the Ext.js library. It causes an ajax call
to retrieve some html to be loaded in the editor body. However,
the call does not work. Sometimes I see it reach the server and
sometimes not. In either case, the ajax return is unsuccessful.

I tried testing by putting the call in fckeditor.html in the WaitForActive()
function and it DOES work. So why does it not work in the fckplugin.js file?

Very confused,
Rob