instance scopes in ghci-6.2.1

Dear GHC developers,

ghci  seems not to work in  ghc-6.2.1 
                (installed from (maybe) RPM on RedHat Linux (maybe) 8).

The interpreter does not find some instances

  > ghci $pcpdocon 
  > ...
   Loading package base ... linking ... done.
   Loading package haskell98 ... linking ... done.
   Loading package lang ... linking ... done.
   Loading package concurrent ... linking ... done.
   Loading package QuickCheck ... linking ... done.
   Loading package readline ... linking ... done.
   Loading package unix ... linking ... done.
   Loading package posix ... linking ... done.
   Loading package util ... linking ... done.
   Loading package data ... linking ... done.
   Loading package docon ... linking ... done.

  Prelude> DExport.factor (10 :: Integer)

  <interactive>:1:
    No instance for (Ring0_.FactorizationRing Integer)
      arising from use of `Ring0_.factor' at <interactive>:1
    In the definition of `it': it = Ring0_.factor (10 :: Integer)

 > :m DExport    does not help this.
   

DExport  is arranged to reexport everything needed from DoCon library
and from Haskell libraries too.

And when it is loaded via intermediate module, it works:

   module T where
   import DExport
   f = factor (10 :: Z)

  > ghci $pcpdocon T 
  >
  > ...
  > factor (10 :: Integer)
  > [(5,1),(2,1)] 


Please, how do we fix the thing?

With kind regards,

------------------
Serge Mechveliani
mechvel@xxxxxxxx