Is it possible to you can post the relevent information from the output window during a build (preferably debug)?
I did a quick search for GLEW with OpenGL 3.X tutorials and ran across this page. I'm know that you are using GLFW and this uses Win32/MFC, but maybe the GLEW parts can help you to check against your own code.
Another thought that just popped into my head is that maybe GLFW is interfering with GLEW (or vice versa). If its possible, try switching out GLFW for SDL or SFML (or even freeglut) and try testing it again.
If all else fails, it might just be easier to switch to GL3W.
EDIT: I was just browsing through the forums here and found this thread where the OP has a similar problem to the one you are describing. It may or may not help, but I'm just gonna put it out there for you. You can check the final post for his resolution to the problem.