importing TIFF into GRASS

Dear Grass-Users,

I have a MUSE raster file that I converted into TIFF file. When I try to
import it in Grass 4.1.5 using r.in.tiff, I got the following error message:

only handle 1-channel gray scale or 3-channel color

I've tried to change the color dispaly using XV, and saving the file in
grayscale. But it doesn't works.

Does anybody knows the answer?

Antonio Rodríguez V.
IRNAS-CSIC
Sevilla, Spain