At which point are you defining the light’s position? The usual way to do it is after setting the world matrix in the modelview matrix (for example, after gluLookAt).
Also, if you enable GL_COLOR_MATERIAL, you have to use glColor to define material properties, not glMaterial.
If lighting works without textures and doesn’t work with, you probably have your texture environment set to GL_REPLACE or GL_DECAL. Set it to GL_MODULATE and the lighting should show up.