What is wrong with this m file?

[Dr. Krishna Mohan, T. R]

I have a simple m file which plots my data in different shades. When I run this 
on my Mac Desktop (Lion), I get blank plot windows opening up but no plot 
appearing. I also get gnu plot general help read me displayed. What is going 
on? The file in question is:

close all;
clear all;
figure;
%
k2 = 176259;
brghtpar=0.5;
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s=load('-ascii','binke.dat');
a=s(1:k2,1:100);
cmap=contrast(a);
newmap=brighten(cmap,brghtpar);
imagesc(a)
colormap(newmap)
%
Dr. Krishna Mohan, T. R
CSIR Centre for Mathematical Modelling and Computer Simulation (C-MMACS)
NAL WTC Road
Bangalore 560 037, India
Tel: +91-80-2505 1927
Fax: +91-80-2522 0392