My preloader doesn't want to work

Question

I'm creating a website using Flash CS5 and AS3.
For this website I've put a preloader on the 1st frame and the site on the 2nd.
I've tested the site after having created a small animation which makes appear the main menu, a logo and an image.
Everything did work good, so I went on building the site.
Now that I have created some pages I've tested again the whole site and the preloader doesn't work anymore.
Testing the site on the "ctrl+enter" window and simulating the download I have a white background (both the preloader and website background are yellow) then I see the preloader for a fraction of second and suddenly the site appears.
Publishing the site on my web space the background is correctly yellow, but the preloader doesn't appear, the browser's loading bar stops at half then the preloader appears again for a fraction of seconds and suddenly the site appears (tested on Firefox, IE, Opera, Chrome and Safari, same behaviour with all of them).
It looks that the preloader is become part of the site and that there is an invisibile preloader.
The setting in: Publish settings -> Flash -> Script Settings -> Library Path -> Default Linkage
is set to "Merged into code"
the same happen if I set "Runtime Shared Library" and "Custom Preloader Loop".
Instead if I set the default preloader (ActionScript 3.0/rsls/loader_animation.swf) it appears correctly.
My preloader should be good since it did work and I haven't modified it.
What could cause this problem?

Answer 1

in your new fla that will load your main swf, you can start with:
var tf:TextField=new TextField();
addChild(tf):
tf.multiline=false;
tf.text="0% Loaded";
tf.autoSize="left";
tf.x=(stage.stageWidth-tf.width)/2;
tf.y=(stage.stageHeight-tf.height)/2;
var ldr:Loader=new Loader();
ldr.contentLoaderInfo.addEventListener(Event.COMPLETE,completeF);
ldr.contentLoaderInfo.addEventListener(ProgressEvent.PROGRESS,progressF);
ldr.load(new URLRequest("main.swf"));  // assuming main.swf is the correct file name
function complete(e:Event):void{
ldr.contentLoaderInfo.removeEventListener(Event.COMPLETE,completeF);
ldr.contentLoaderInfo.removeEventListener(ProgressEvent.PROGRESS,progressF);
removeChild(tf);
addChild(ldr);
function progressF(e:ProgressEvent):void{
tf.text=Math.round(100*e.bytesLoaded/e.bytesTotal).toString()+"% Loaded";