Flex 4 styleManager loadStyleDeclarations fail

Question

I am starting to tinker with Flex 4 and I am having trouble trying to load a style swf file.  I have a css file that looks like this
@namespace s "library://ns.adobe.com/flex/spark";
s|Application {
    background-color: red;
which I compiled to a css-based swf file.  The code I am using to load the swf is like this:
// Called within a function
var dispatcher : IEventDispatcher = FlexGlobals.topLevelApplication.styleManager.loadStyleDeclarations(themeSwfUrl);
dispatcher.addEventListener(StyleEvent.ERROR, onStyleError);
dispatcher.addEventListener(StyleEvent.PROGRESS, onStyleProgress);
dispatcher.addEventListener(StyleEvent.COMPLETE, onStyleComplete);
private function onStyleError(event : StyleEvent) : void {
    trace("\tLoadThemeCommand.onIOError(event)");
    trace(event.errorText);
    Alert.show(event.errorText, "Theme Load Failure");
private function onStyleProgress(event : StyleEvent) : void {
    trace("\tLoadThemeCommand.onStyleProgress(event) " + event.bytesLoaded + " / " + event.bytesTotal);
private function onStyleComplete(event : StyleEvent) : void {
    trace("\tLoadThemeCommand.onLoadComplete(event)");
    trace('event.target: ' + (event.target));
    var dispatcher : IEventDispatcher = event.target as IEventDispatcher;
    trace('dispatcher: ' + (dispatcher));
    dispatcher.removeEventListener(StyleEvent.ERROR, onStyleError);
    dispatcher.removeEventListener(StyleEvent.PROGRESS, onStyleProgress);
    dispatcher.removeEventListener(StyleEvent.COMPLETE, onStyleComplete);
I see the following traces:
LoadThemeCommand.execute(pNotification)
LoadThemeCommand.onStyleProgress(event) 0 / 24042
LoadThemeCommand.onStyleProgress(event) 8192 / 24042
LoadThemeCommand.onStyleProgress(event) 16384 / 24042
LoadThemeCommand.onStyleProgress(event) 24042 / 24042
But I am getting this error:
Error: Compatibility version has already been read.
    at mx.core::FlexVersion$/set compatibilityVersion()
    at mx.core::FlexVersion$/set compatibilityVersionString()
    at TestTheme_mx_core_FlexModuleFactory()
I've looked around but can't find anything to help me.

Answer 1

I figured it out.  I was using FDT to compile the project and it was using the Flex 4 SDK to compile.  But when I compiled the css file to a swf, I was using the command prompt.  And my FLEX_HOME was still looking at the Flex 3.5 SDK.  Dumb noob mistake.