Error 5000: The class ‘..’ must subclass ‘flash.display.MovieClip’ since it is linked to a library symbol of that type.

We work in Flash CS4, and save our files in Flash CS3, and sometimes when we publish the swf file from the Flash CS3 FLA, we get this error:

Error 5000: The class '..' must subclass 'flash.display.MovieClip' since it is linked to a library symbol of that type.

Replace “..” with whatever class you use. The solution to this problem is pretty simple.

1. Select File > Publish Settings

2. Click on the Settings button

3. Unckeck “Automatically declare stage instances”

4. Click OK and that’s it! Now it should work.