[Haskell-beginners] Loading QuickCheck in GHCi.

Dear All, Whenever I tried to load QuickCheck in GHCi, I met the following problem: Prelude> :l Test.QuickCheck <no location info>: module `Test.QuickCheck' is a package module Failed, modules loaded: none. Test.QuickCheck seems to be a module anyway, bit it couldn't be loaded directly by issuing the command. I don't understand why. Thanks in advance. Kwanghoon PS. Of course, I installed QuickCheck-2.1.0.3, and I can use it when I load it by loading some haskell program having "import Test.QuickCheck".