UIMovieClip error

I have several flex components that I exported from flash in my Flex application.?For some reason, whenever the focus gets changed from the custom component I get the following runtime error:

TypeError: Error #1009: Cannot access a property or method of a null object reference.

at mx.flash::UIMovieClip/removeFocusEventListeners()[E:\dev\flex\sdk\frameworks\pr ojects\flash-integration\src\mx\flash\UIMovieClip.as:2368]

at mx.flash::UIMovieClip/focusOutHandler()[E:\dev\flex\sdk\frameworks\projects\fla sh-integration\src\mx\flash\UIMovieClip.as:2411]

Any ideas on what could cause this?

UIMovieClip error

I'm still not sure why I hade the error exactly.?As it turns out, Flex was compliling to Flash Player 9.?To fix the problem I changed the Require Flash Player Version in poperties under Flex Compiler to 10.0.0.

I generally don't like to generate an html wrapper and tend to use the projecter only.?Even after changing the flash version here, flex still compiled in flash player 9 when I didn't choose to generate the HTML wrapper.?To fix this problem, follow the instructions here:

http://opensource.adobe.com/wiki/display/flexsdk/Targeting+Flash+Player+10