Here is the problem:
http://img11.hostingpics.net/pics/593315Sanstitre.png
in my source file, I imported as3isolib to make my own game. But unfortunately, FlashDevelop is not able to find the import that i am doing in my main class!
Thank you for helping me, I'm new with AS :)
Fixed I made a huge mistake, you only need to add the file in "src" from as3isolib.