Flash MX Saving a File in Flash 8 Format... Why?

Hi everyone, just wanted to know exactly what is the deal with opening up a flash file i created in mx and then saving it as flash 8 format.

I was just working on a file I created in mx. I went to publish settings and set it to flash 6 and published. File worked flawlessly. Then I hit save later on after some work and it said saving to flash 8 destroys certain things if u want you can use save as to save as flash mx format. I figured well since my publish settings are correct (flash 6) why not just save it so I did and wham my flash file stops working.

Anyone define exactly why my file is not working now. Its a basic mp3 file player. :{