Resolving dependencies...
Downloading bla-2009.10.20...
Configuring bla-2009.10.20...
Building bla-2009.10.20...
Preprocessing executable 'bla' for bla-2009.10.20...

src/bla.hs:1:8:
    Ambiguous module name `Prelude':
      it was found in multiple packages: base haskell98-2.0.0.2
Failed to install bla-2009.10.20
cabal: Error: some packages failed to install:
bla-2009.10.20 failed during the building phase. The exception was:
ExitFailure 1