Undefined property error with Event.CLOSING

Question

I was using the Flex 3.5 + AIR 2 beta 2 SDK for some time now for one of my projects. Moving to the final 3.5 release today causes the compilation to fail with the following error.

Error: Access of possibly undefined property CLOSING through a reference with static type Class.

This happens in the following line.

this.addEventListener(Event.CLOSING, this.m_dlgQuitCreate);

This line is in the creationComplete event handler of a class which extends the import mx.core.WindowedApplication.

Moving back to the beta 2 release of the SDK does not cause this error. Anybody else faced a similar issue before?