The version of OpenGL included in the Haskell Platform (OpenGL 22.214.171.124) has a known "vertexAttribPointer undefined" bug:
It is apparently easy to fix (remove the "undefined" line as per the previous post).
This is a major "show stopper" bug because it makes it impossible to use OpenGL shaders with the Haskell Platform => can't demonstrate how useful and practical the Haskell Platform is for creating modern looking games.
(OpenGL 2.3.0 has fixed the issue - post here:)
The current Haskell platform contains the fix, closing...