patrick scheibe wrote:

[...] and got error-messages like

Module `GL' is located in package `Main' but its interface file claims it is part of package `HOpenGL'

These are not error messages, but warnings. They can safely be ignored and vanish if a more recent GHC is used, IIRC.

[...] Is there somebody who can give me a short makefile to see what was wrong. [...]

To see which flags are needed if HOpenGL is not installed, have a look at the log of the build process where the examples subdir is built. If you did a "make install", no complicated Makefile is needed, just issue: ghc --make -package HOpenGL Hello.hs For more info on packages see http://haskell.org/ghc/docs/latest/set/packages.html Cheers, S.