Hello Cafe! I asked about this problem on IRC channel but with little luck. The problem boils down to the following: readline crashes on any input if the calling program runs in the Emacs buffer. To reproduce this bug, load the code below into ghci using haskell-mode and run main.

import System.Console.Readline

main = do readline "prompt" putStrLn "You cannot see this, because I've crashed. Amen"

I'm running Windows 2003 Server, GHC-6.6, Emacs 22.0.50.1.