Follow the following steps:
--In flash, go to File > Publish Settings
--Click the spanner icon next to the Script dropdown
--In Document class enter Overlay
--Click OK on both windows.
+- In flash, go to File > Publish Settings
+- Click the spanner icon next to the Script dropdown
+- In Document class enter Overlay
+- Click OK on both windows.
Overlay.as is the entry point for the application, you will want to edit it to your needs.