[Haskell-cafe] How do I fix this error message?

[Michael Vanier]

Hi everyone,

I ran into this error when recompiling some code I hadn't worked on in a 
while:

Foo.hs:19:7:
    Could not find module `Control.Monad.Error':
      it was found in multiple packages: monads-fd-0.0.0.1 mtl-1.1.0.2

I gather that monads-fd is supposed to be a replacement for mtl, but I 
have both of them (mtl from the normal GHC 6.10.4 install, monads-fd 
from cabal).  I don't really care which one I use, though mtl has been 
fine in the past.  In the past, I had to manually uninstall cabal 
packages that used incompatible libraries.  Is this still the case?

TIA,

Mike