Okay so I am hot on the trail of a bug in my AS3 application.  I save my application only to notice the following error message:

Unable to resolve resource bundle “styles” for locale “en_US”.

I say to myself “WTF” and just assume that my workspace is hosed.  I the rebuild my workspace only to be greeted by the same error message!

After about 4 hours of headbanging I am ready to reinstall Flexbuilder when I figure out what went wrong.  It turns out that I accidentally tried to include a class in the mx namespace in to an ActionScript project.

Here is the moral of the story.  If ever you find yourself with the above error message and you are working in a pure ActionScript project make sure your code does not have an import statement that references mx.