problems using graphviz perl module from apache (windows)

[Sergio]

I'm writing a cgi script that uses graphviz (the dot program) to
generate a graph and I'm banging my head against the wall trying to get
it to work properly. Currently, if I run the script directly from the
command line, it will work properly and generate my graph (which gets
dumped into a file). If I invoke the script as a cgi script within
apache, it runs fine until it calls the as_png() function, at which
point it will die waiting for a result (the destination file is created
but is empty).

I'm running SERVER_SOFTWARE="Apache/2.0.52 (Win32)"
and version 1.8 of the GraphViz module. If I run a printenv.cgi, I get
the following path:

PATH="C:\Program Files\Perl\bin\;C:\Program Files\Reflection;C:\PROGRAM
FILES\THINKPAD\UTILITIES; C:\Program
Files\Java\j2re1.4.2_01\bin;C:\WINNT\system32;C:\WINNT;C:\WINNT\System32\Wbem;C:\Oracle\ora81\bin;C:\Program
Files\Oracle\jre\1.1.7\bin;C:\ISIS;C:\PROGRA~1\COMMON~1\MDL
Shared\ISIS;C:\PROGRA~1\ATT\Graphviz\bin;C:\PROGRA~1\ATT\Graphviz\bin\tools"

which does seem to have the correct path settings for dot.exe.

The error that the apache log gives me is: Premature end of script
headers: simplegraph.pl

If I remove the line that calls as_png(), the script runs fine.

Any assistance would be most appreciated. I've searched usenet but to
no avail...

Thanks!

Sergio.

 

[Sergio]

Another piece of the puzzle: The CGI script *does* seem to be
correctly invoking the dot.exe program. However, dot.exe is running
forever and never comes back, which is why the cgi script remains
seemingly hung... I notice that graphviz.pm calls dot.exe using a
"run" command. I'm not familiar with it... Any hints?

Sergio.