Problem with loading times

Hello, I was wondering if anyone can help! I will try my best to explain my problem.

Basically I have a webpage full screen with a flash movie and a button that opens up a borderless window with the main sight on it.

[COLOR=darkorange][/COLOR]
[COLOR=black]This is the code of the button.[/COLOR]
[COLOR=darkorange]btn_Up.onRelease = function() {
getURL(“javascript:Launch(‘http://thisisanexample/mainpage.swf’, 1000, 450)”);
};[/COLOR]

Now everything works fine except it seems to load the flash file fully taking up to 10 seconds with a blank page.

The mainpage.swf has a preloader which I obviously hoped would avoid users being left with nothing on the screen.

Is there something simple that i’m doing wrong? Is there any reason why it would load the swf file fully before playing it and allowing the preloader to kick in?

This is for a working progress company site so i cannot post the files. Thanks in advance for any help!

Tris