1) Make sure the id and name are the same in each AC_FL_RunContent function. Just changing one won't work. This way document.getElementById should always find the object on the page.
3) If you're doing local development make sure to check Always allow in Global Security Settings Panel.
I found step 3 after wasting an entire morning looking around the internet. Without this I kept getting this warning.
*** Security Sandbox Violation ***
SecurityDomain 'null' tried to access incompatible context 'file:///foo/bar/project.swf'
Once you're project is finished you might want to change this back. Not sure what thing on the web wants to break your computer.