Reading PDF documents with Perl

Hi all.

I'm new with perl and trying to get a script to read the 'Subject' field
out of a document using PDF::Parse and the following code:

#!/usr/bin/perl -w

use PDF::Parse;

open($pdf_file,"<067232489X.pdf") or die("Cannot open file!");

$pdf->TargetFile($pdf_file);
$pdf->LoadPageInfo;

$subject = $pdf->GetInfo("Subject");

print "The subect of file $pdf is:\n";
print $subject;


I'm not really sure if I've got much of anything right, but I'm getting
the following error trying to run this code:
PDF::Core::PDFGetPrimitive() called too early to check prototype at
D:/StudyPerl
/site/lib/PDF/Core.pm line 288.
PDF::Core::PDFGetPrimitive() called too early to check prototype at
D:/StudyPerl
/site/lib/PDF/Core.pm line 294.
Can't call method "TargetFile" on an undefined value at pdf_check.pl line 8.


Can anyone possibly help me figure out where I'm going wrong with this?

Thanks!