There is an another way to decode the swf file.
1. Open Macromedia Flash
2. Go to File > Import
3. you can select there the swf file ...
4. Open it ... and try to decode ...
but there is a problem. When you import the swf file, it automatically merge all layers to a single layer. So, it's taugh to decode the action scripts to change the content.
If anyone create the way to decode SWF , let me know ...