xmonad hack error message

xmonad.hs:443:29:
    Couldn't match expected type `a -> b'
           against inferred type `XMonad.Layout.LayoutModifier.ModifiedLayout
                                    AvoidStruts
                                    (Choose Full (Choose (Mirror ResizableTall) ResizableTall))
                                    a1'
    In the first argument of `($)', namely `myLayout'
    In the `layoutHook' field of a record
    In the first argument of `ewmh', namely
        `defaultConfig
           {terminal = myTerminal, focusFollowsMouse = myFocusFollowsMouse,
            borderWidth = myBorderWidth, modMask = myModMask,
            workspaces = myWorkspaces, normalBorderColor = myNormalBorderColor,
            focusedBorderColor = myFocusedBorderColor, keys = myKeys,
            mouseBindings = myMouseBindings,
            layoutHook = myLayout $ onWorkspace "8" simplestFloat,
            manageHook = myManageHook, handleEventHook = myEventHook,
            startupHook = myStartupHook,
            logHook = dynamicLogWithPP $ defaultPP {ppOutput = hPutStrLn h}}'