[Haskell-beginners] Empty 'do' constructor

I use Haskell Platform 2010.2.0.0 on WinXP, and jEdit. I write my first code, and got error... main = do cs <- readFile "C:\\SPR.txt" putStrLn $ myManupulation cs myManupulation cs = (unlines cs) ! 3 The error message is "Empty 'do' construct" What's this mean? and how can I fix it? Thank you a lot! -- Sok Ha, CHANG Open Mind Clinic/Academy, 1551-1, Sa-Dong, SangRok-Gu, AnSan-City, KyongGi-Do Tel: 031-407-6114 HP: openmind.ac / www.openmind.ac