Premature end of script header error....

This is a piece of code to print a graph object.

####
.....<code to generate/plot a graph skipped>
....
       print "content-type: image/$graph_format\n\n";
        binmode STDOUT;
        print $img_obj;
....
####
This code works fine for me and I am able to see the graph. But when
the code goes on production     server, it gives Internal Server
Error. I have check the error logs and it says the premature end of
header.

I have check all the graph modules GD, GD::TextAlign, GD::Graph all
are same on both machines.

I use Apache 2.0.52, Perl 5.8.5
while the production runs Apache 1.3.29 , perl 5.8.0

Is there any compatibility issue or is there something I dont know
about.