Haskell PFP库问题

Question

我正在尝试使用examples运行这些library。当我运行命令ghci Dice.hs时，即使我与Dice.hs在同一个文件夹中它也告诉

$ ghci Dice.hs
GHCi, version 7.6.3: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.

Probability.hs:5:8:
    Could not find module `Monad'
    It is a member of the hidden package `haskell98-2.0.0.2'.
    Use -v to see a list of the files searched for.
Failed, modules loaded: none.

我还在Cabal中安装了mtl包。其他想法？