Grdimage - PSL error

Hi,

I am trying to plot a DEM in grayscale using grdimage and grdconvert.

First, I use grdconvert input_file (in geotiff) file.grd
grdimage file.grd -JX17c/12c -R453000/1987000/2910000/4400900 -D -V >> outfile.ps

These commands worked sometime back, but now it gives me a PSL error and then the output is basically compressed. Not sure why this compression is happening.
Any suggestions on how to resolve this error. Many thanks.

Please ignore the makecpt log
slope_dynamics_HMA_v3.ps (38.2 KB)

I see no PSL error, just a warning message when it writes out the compressed image. The fact it compresses down to 0.3% probably means that most of the pixels are identical (black it seems). So hard to tell more without knowing the range of the grid and what my2.cpt is doing.