SPOT image processing

[a907tape at diamond.sara.nl]

This is a problem that concerns SPOT image rectification in GRASS4.0.
We have a Spot image of North Benin (63-328) with the following lat long coordinates for the corner pixels:
upper left (c1) N0111933 E0023045
upper right (c2) N0111435 E0030304
lower left (c3)  N0104742 E0022331
lower right (c4) N0104244 E0025545

with m.ll2u we calculated the utm coordinates for these points, using spheroid wgs84 in zone 31. Results (east north) (without decimals):
c1 446802   1252051
c2 505578   1242854
c3 433527   1193378
c4 492254   1184160

We created a location BENIN with default region limits in utm:
north  1383127
south  663305
west   228285
east   610674
and resolution of 20x20 meters.
We created a mapset SPOT in this location.
We extracted the image from tape with i.tape.other creating the normal output:b.1, b.2, b.3 all with similar rows and columns and regions. A group was created and targeted to the relevant utm location and mapset (BENIN SPOT).
i.points was used to identify the four corners and administer the correct coordinates. finally i.rectify was started. Having tried this in various ways and running r.support on both input and output does not help: the result is always the same: a geographically rectified rastermap with appropriate parameters (region and resolution) and with the cell_file of considerable size (around 10 Mbyte) and all support files but with ALL PIXELS HAVING CATEGORY 0 (no data).
We ran both i.rectify option 2; "determine the smallest region which covers the image", using the entire BENIN area as target location and we also created a much smaller target location just the size of the geographic region that the rectified image would cover and then opted for version 1: "use the current region in the target location"; again empty rastermaps as result.
The following error message was mailed by grass: "GIS error: unable to write row 0" (somtimes other row numbers were indicated). Questions:
1 any solutions for this problem;
2 can an image be rectified in lat long (i.points seems to ask for utm, state plane or xy)
3 i.tape.other seems to shift the image 33 colomns to the right; how can this be avoided