[Haskell-cafe] cabal update error

Hi all, I just installed the Haskell Platform, and when I try "cabal update", I have the following output:

Downloading the latest package list from hackage.haskell.org cabal: failed

This error does not give me information about what is wrong. Has anyone had this error before? I would appreciate an explanation (or possible explanation), rather than an "update it manually". Thanks in advance. -- Daniel Díaz