title: Flex compiler error: "please put definition in a package" for classes that ARE in a package
body: <p>This is with Flexbuilder 3.2, Eclipse 3.3.2.</p>
  
  <p>I am moving my development environment to a new machine.  Actionscript classes that compiled in the old environment now get a compile error:</p>
  
  <pre><code>A file found in a source-path must have an externally visible definition. If a definition in the file is meant to be externally visible, please put the definition in a package.
  </code></pre>
  
  <p>I do declare the package in these classes - I think failure to declare the package is the usual reason for this error.</p>
  
  <p>To add to the mystery, many classes in this project compile without errors.</p>
  
  <p>What should I check to diagnose this?</p>