non-power-of-two indexed texture lookup

I am using 8 bit indexed texture lookup with glColorTable() and it works fine, but when I use a non-power-of-two texture with gl_texture_rectangle_nv along with glColorTable, my texture does not display correctly? Are these two operations not compatible with each other?

You can’t use glColorTable with rectangular textures. You should be getting an INVALID_ENUM error if you are passing GL_TEXTURE_RECTANGLE_NV as the target parameter of this function.