TIFF to GRASS

[valerio noti]

Dear Grass Users,

J am a GRASS beginner....
J have tried to import a TIFF-file in GRASS with the command
"r.in.tiff".
Here is the entire results:
#r.in.tiff input=x.tif output=y.tif

Warning, TIFF directory is missing required "StripByteCounts" field, calculating from imagelenght.
Reading x.tif.....TIFF Directory at offset 0xf416
Subfile type: (0=0x0)
Image widht 7200 Image Lenght 6646
Resolution 300, 300 Pixels/Inch
Bits/sample:1
Compression Scheme: CCITT Group 3 facsimile encoding
Photometr. Interpretation: min-is-black
Samples/Pixel:1
Rows/Strip:6646
Planar configuration: Single image plane
Group 3 Options: (0=0x0)
1 strips:
        0: [             24,         62462]
ERROR: Only handle 1-channel gray scale or 3-channel color.

J have tried to change Compression Scheme and resolution but with the same results.
J have then converted the TIFF file in GIF format and used the command "r.in.gif" but it seems  this command doesn't work (the result is "no match").
Is it possible to replace this only file and where can j find it?
Sorry for bad english.

Valerio