Stumped on preloading site

I’ve been creating a site and have been encountering much resistance with regards to implementing a preloader. As I have read in many tutorials, I have removed everything from the first frame of the main timeline. Here I have placed my wonderful preloader, however it doesn’t show up until 90ish percent of the .swf has loaded.

If you look at the images below, I have removed the preloader from the first frame, so it is completely blank, yet you will notice that when I publish it, it indicates that the first frame contains over 2MB of ‘something’ that it needs to load. My file contains multiple nested movie clips, movie clips exported for actionscripting that I load dynamically as the user explores, and I reference the occasional external file.

I am totally perplexed as to what is contained on this first frame, as it is preventing any sort of preloader from being used. Should I restructure the file some way? Should I load this file into another .swf? Any suggestions would be greatly appreciated.