Odd problem when saving to eps/ps


I am using Python 2.4.4, Numpy 1.1.1 and Pylab 0.98.3 and have a problem
with saving to eps.

Basically I create 7 plots, each with 2 subplots of which one is an
imshow colour map and the second is a simple plot(). When saving them to
eps I can display 5 out of 7 with ghostview but 2 of them fail to
display. Setting the file type to PNG I can get all 7 out but this is
for a ps latex document so I need eps. If I turn off the plot() subplot
I can get all 7 out into eps. All 7 plots are effectively the same just
with different data and all 7 display fine via the backend Tkagg.

Any ideas