It’s a simple tips about the VerifyError like #1079. When you start you app by upgrading you flex sdk or complie a relatively complex Flex (SDK 4.0) project with several Library projects, probably you will take the error like: VerifyError: Error #1079: Native methods are not allowed in loaded code. Sometimes even the code basically looks like this:

var xm:XML = <root></root>;
trace(xm);

Only create a new XML object and trace it out.

In fact, this error is caused by trying to load playerglobal.swc. We can fix it simply change to playerglobal.swc be linked as "external".