[Haskell-cafe] flow2dot

I've installed the flow2dot utility. It fails to produce a dot file from the sample provided by it's author. The output of the program is: .cabal/bin/flow2dot sample.flow flow2dot: Input: order a b c d a -> b: let's play "catch a ball"! b -> c: i'll pass it along c: what to do next? c -> a: lets throw it back again a: "not fair!" a -> c: find someone else! c -> d: ok, here you go: catch! d: zZzZzZzZzzz.... Error: "sample.flow" (line 1, column 1): unexpected "o" expecting "->", ":" or end of input