Preloader Issue

Hi,

After publishing my project to an SWF, I can then open it and mess around with it, no problem. It works perfectly. I then attach a preloader to it, simply calling the SWF, and it tells me that I have some null object in one of my classes. I have tried different preloaders, and its the same every time.

Here is the preloader I am currently trying out:
http://doogog.com/actionscript-3-external-preloader.html

Again, I can double click my SWF and it works beautifully. When I try to load it, using this preloader, it tells me that there is a null object or reference in one of the first classes it needs to call upon.

No idea what could be wrong. All of the folders and files I need are all there, untouched.

Thanks for any help :fab: