[Haskell-beginners] Help with GHC Packages Installation on Fedora 14

Hi, I installed a Fedora 14 virtual machine on my home Windows desktop. Then I tried to install GHC packages on Fedora by typing "yum install ghc" as root, and got the following error: "Error: Cannot retrieve repository metadata (repomd.xml) for repository: fedora. Please verify its path and try again." What should I do now to fix this error? Thanks, Hong