Picasso does not create graph image

[abernard at chez.com]

I'm trying to install argus 3.6 on apache 1.3.34 with mod-perl enabled
and i'm having some problems with new picasso graph tool.
Picasso does not create any graph image.
After making some tests I noticed that the CGI program fails to
communicate with Picasso program as nothing is read on stdin (even if
the input flow seems to be ok; used for a static command line call).
If I prepare in a text file the input feed for picasso the command
successfully create the png graph.

 /usr/local/argus/lib/picasso -stdin 1 < picassoIn.txt > img.png

Is this a apache issue due to pipe communication between perl-cgi an
Picasso (code a bit tricky ;)) or Argus issue ?
Any idea, tip ?

Thanks,