Error: Checksum (md5) mismatch for ghc-6.6.1-src.tar.bz2
Error: Target com.apple.checksum returned: Unable to verify file checksums
Error: Status 1 encountered during processing.
could you try downloading the right distfile, editing the Portfile (port edit ghc) with the right checksum, and see if it works? Could be a broken download, could be just an inaccurate checksum.