FlexUnit 4.1.0-8 Error 1046

Hi,

I'm using Eclipse Gallieo on Mac OS 10.6.8 with the Flash Builder 4 plugin.  My project is using the Flex 4.5.0 SDK and I recently updated FlexUnit from 4.0 to 4.1.0-8.  Now when I compile I get four errors:

1. 1046: Type was not found or was not a compile-time constant: [flash.events]::IEventDispatcher.
2. 1046: Type was not found or was not a compile-time constant: [org.flexunit.async]::IAsyncTestResponder.
3. 1046: Type was not found or was not a compile-time constant: [org.flexunit.internals.runners.statements]::IAsyncHandlingStatement.
4. 1046: Type was not found or was not a compile-time constant: [org.flexunit.internals.runners.statements]::IAsyncStatement.

I can still run my unit tests if I tell Flash Builder to ignore the errors and everything seems okay but this is a) annoying and b) indicative of something being wrong somewhere.  So my question is: what do I need to do to resolve this?  Or what could be the cause of this?