Flex 3.4 Illegal override of FlexModuleFactory

An important note for those switching from Flex 3.2 to Flex 3.4

If you have css styles which were compiled (likely in FlexBuilder), you must re-compile them with the Flex 3.4 SDK to get rid of this error.

Line Causing Error

StyleManager.loadStyleDeclarations("yourexternalstyles.swf");

Exact Error Message

VerifyError: Error #1053: Illegal override of FlexModuleFactory in mx.core.FlexModuleFactory.

at global$init()