Help me with this texturing please.

I have a Model made, I have it all mapped, I have the texture image made but when I go to export it as a .NIF I get an error that says…

“Error: Texture ‘Tex’ Must be of type IMAGE or ENVMAP”

What does this mean and what do I do?

Note: I am fairly new to blender and am trying to use it for modding The Elder Scrolls III Morrowind, this would be my first textured model if I can get it to Export.

Thankyou in advance.

You need to use a UVMapped Texture.