On Mon, Feb 24, 2014 at 1:20 PM, Derek Mahar <derek.mahar@gmail.com> wrote:

[dmahar@dmahar haskell-platform-2013.2.0.0]$ cabal update

Downloading the latest package list from hackage.haskell.org
Note: there is a new version of cabal-install available.
To upgrade, run: cabal install cabal-install
[dmahar@dmahar haskell-platform-2013.2.0.0]$ cabal install cabal-install
Resolving dependencies...
Configuring HTTP-4000.2.11...
Building HTTP-4000.2.11...
Preprocessing library HTTP-4000.2.11...

Network/Stream.hs:35:8:
    Could not find module `Control.Monad.Error'
    There are files missing in the `mtl-2.1.2' package,
    try running 'ghc-pkg check'.
    Use -v to see a list of the files searched for.
Failed to install HTTP-4000.2.11
cabal: Error: some packages failed to install:
HTTP-4000.2.11 failed during the building phase. The exception was:
ExitFailure 1
cabal-install-1.18.0.2 depends on HTTP-4000.2.11 which failed to install.

'ghc-pkg -v check' reports that my Haskell environment is missing many files and that many of its packages are broken.  See the attached output of 'ghc-pkg -v check'.