Cryptic error message

Hi!

This is not really a bug but a request for better error messages. A couple
of minutes ago I got the following:

Constraints.lhs:42:
    Couldn't match `* -> *' against `Type bx'
        Expected kind: * -> *
        Inferred kind: Type bx
    When checking that `Annotation' is a type
    In the data type declaration for `AConstraint''

Now what is Type bx? I suppose ghc is telling me that Annotation should
either have kind * or # but its rather cryptic.

> ghc --version
The Glorious Glasgow Haskell Compilation System, version 5.04

        /Josef