Just in case anyone else here has to bash their head over this like I did, here's how I fixed it. I ended up having to link GLEW statically using glew32s as my lib instead of glew32. Also, before I included the GL/glew.h header file in my code, I did a #define GLEW_STATIC and it ended up working. I'm still not sure why I can't get GLEW to work dynamically with Code::Blocks/MinGW32...