[Haskell-cafe] hClose: invalid argument (Invalid or incomplete multibyte or wide character)

[Johannes Waldmann]

I have this program

main =  writeFile "check.out" "ü"

that's u-umlaut, and the source file is utf-8-encoded 
and ghc-6.12.3 compiles it without problems but when running, I get

hClose: invalid argument (Invalid or incomplete multibyte or wide character)

(debian 5.0.6, kernel 2.6.18-6-686. I know that's somewhat dated.
Would upgrading help?)

Regards - J.W.