I see that you're using glew, have you called glewInit()
?
Also make sure you're checking if the initialization was a success.
GLenum err = glewInit();
if (GLEW_OK != err)
{
/* Problem: glewInit failed, something is seriously wrong. */
fprintf(stderr, "Error: %s\n", glewGetErrorString(err));
}
OR, It could be something like this it happened to me this morning, a restart solved my problems