[Haskell-cafe] problem with cabal for syb-with-class

[Andrew U. Frank]

i tried to install wxGeneric and need syb-with-class.
i got the package from hackage.
configure runs fine, but when i build i get:

Data/Generics/SYB/WithClass/Instances.hs:11:7:
    Could not find module `Data.Array':
      it is a member of package array-0.1.0.0, which is hidden

but array-0.1.0.0 is installed, as shown later.
what can be wrong? why is an installed package complained about as
hidden?

thanks for help!

andrew

frank at bernH:~/haskellSources/packages/syb-with-class-0.3$ ghc-pkg
describe array
name: array
version: 0.1.0.0
license: BSD3
copyright:
maintainer: libraries at haskell.org
stability:
homepage:
package-url:
description: This package defines the classes @IArray@ of immutable
arrays and
             @MArray@ of arrays mutable within appropriate monads, as
well as
             some instances of these classes.
category:
author:
exposed: True
exposed-modules: Data.Array Data.Array.Base Data.Array.Diff
                 Data.Array.IArray Data.Array.IO Data.Array.MArray
Data.Array.ST
                 Data.Array.Storable Data.Array.Unboxed
hidden-modules: Data.Array.IO.Internals
import-dirs: /usr/lib/ghc-6.8.2/lib/array-0.1.0.0
library-dirs: /usr/lib/ghc-6.8.2/lib/array-0.1.0.0
hs-libraries: HSarray-0.1.0.0
extra-libraries:
extra-ghci-libraries:
include-dirs:
includes:
depends: base-3.0.1.0
hugs-options:
cc-options:
ld-options:
framework-dirs:
frameworks:
haddock-interfaces: /usr/share/doc/ghc6-doc/libraries/array/array.haddock
haddock-html: /usr/share/doc/ghc6-doc/libraries/array
f