Seems okay to me if I use sha256. I can't reproduce the hash you got with any of the algorithms shasum offers.
[callen@atlantis ~/Downloads]$ sha256sum Haskell\ Platform\ 2014.2.0.0\ 64bit.signed.pkg
62f39246ad95dd2aed6ece5138f6297f945d2b450f215d074820294310e0c48a Haskell Platform 2014.2.0.0 64bit.signed.pkg
[callen@atlantis ~/Downloads]$ sha1sum Haskell\ Platform\ 2014.2.0.0\ 64bit.signed.pkg
5741fc1d9253568d3388fbe21c41d746acede9ab Haskell Platform 2014.2.0.0 64bit.signed.pkg
[callen@atlantis ~/Downloads]$ sha224sum Haskell\ Platform\ 2014.2.0.0\ 64bit.signed.pkg
6f5254d1ac958001eb93f1e30b4df0f34f372b791abd4bf66fd88c74 Haskell Platform 2014.2.0.0 64bit.signed.pkg
[callen@atlantis ~/Downloads]$ sha512sum Haskell\ Platform\ 2014.2.0.0\ 64bit.signed.pkg
7f6a0e90966c3cc7f5000b4d2e92414a4959a22a6fed445547d9b01418bc4e4e3f391e3ec5f7713875753932a1b4880c57c30a3683885bb0209136080e6cb32c Haskell Platform 2014.2.0.0 64bit.signed.pkg
[callen@atlantis ~/Downloads]$ sha384sum Haskell\ Platform\ 2014.2.0.0\ 64bit.signed.pkg
63fed8f9b8e8b51421462e0d12e45a8baa50e14640bc4f7ce8cbbfdc20f11cb8e0af5f1aee32c312f891569e95454ceb Haskell Platform 2014.2.0.0 64bit.signed.pkg
[callen@atlantis ~/Downloads]$ sha224sum Haskell\ Platform\ 2014.2.0.0\ 64bit.signed.pkg
6f5254d1ac958001eb93f1e30b4df0f34f372b791abd4bf66fd88c74 Haskell Platform 2014.2.0.0 64bit.signed.pkg