Some graphics not loading, even with preloader

Hello,
I’ve got a swf that i’m using from several location throughout a course Web site. Lesson 1 embeds the same swf as Lesson 2. In each lesson I pass a variable to the SWF to tell it which lesson data it needs to access. See below. The exercise_var=0 tells the swf to load the data from the childnode that is 0. Lesson 2 would have an exercise_var=1, etc…


var fo = new FlashObject("…/6568-00.swf?exercise_var=0", “animationName”, “450”, “500”, “8”, “#FFFFFF”);

The following code is in the SWF and loads the XML info:

function loadXML(loaded) {
if (loaded) {
xmlNode = this.firstChild;
_global.conflict_var = xmlNode.childNodes[exercise_var].childNodes[0].firstChild.nodeValue;
_global.verdict_var = xmlNode.childNodes[exercise_var].childNodes[1].firstChild.nodeValue;
_global.answer_var = xmlNode.childNodes[exercise_var].childNodes[2].firstChild.nodeValue;
gotoAndStop(“main”);
} else {
content = “file not loaded!”;
}
}
xmlData = new XML();
xmlData.ignoreWhite = true;
xmlData.onLoad = loadXML;
xmlData.load("…/hs-6568.xml");

This all seems to work and I also added a preloader but sporadically I’m finding that not all the graphics in my SWF are loading and I have to hit refresh to reload the movie. Any ideas why some of my stage items are not loading on random pages? I grouped the graphics on the stage and made them a grahpic movie clip hoping this would force them to load. But it hasn’t worked.