[Haskell-beginners] Empty 'do' constructor

[Sok H. Chang]

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
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