srikrishnan:

I'm sorry, but I'm unfamiliar with both Image::ExifTool and the internals of .pdf files. I'm writing just to offer a suggestion or two.

First, I notice that you restrict your variable names to 8 characters. While I'm a fan of shorter variable names, I'm surprised that you're wasting three of your characters by using a suffix of 'Val' on (nearly) all variables. I'd drop that habit like a hot rock. It's much more important to make your variable names clear than short.

For example, suppose you have a variable to represent a store owners Social Security Number. If you're a Java programmer, you might wind up with StoreOwnersSocialSecurityNumber or some such, which is much too long for my comfort. It looks like you might try to pack it down to $StOSSVal. I tend to use standardized abbreviations in my code to shorten variable names. In any industry, you'll have a particular set of frequently-used terms, and you should have (or create) a set of standard abbreviations for those terms. For example, a very common contraction of Social Security Number is SSN, so I'd use that throughout the application. So I'd shorten the variable to $StoreOwnerSSN, which is short and clear.

Secondly, it appears that the majority of those variables are used only once. Looking at how you're using them suggests the use of a hash, something like:

use strict;
use warnings;
use Image::ExifTool ':Public';

my @PDFAuthors = (
    "Michael L. Oldham",
    "Dheeraj Khare",
    "Florante A. Quiocho",
    "Amy L. Davidson",
    "Jue Chen"
);
my %StdPDFattrs = (
    Description => "XXX 450, 515 (2007). doi:10.1038/XXX06264",
    Format => "application/pdf",
    Publisher => "XXX Publishing Group",
    Rights => " 2007 XXX Publishing Group",
    Charset => 'Latin',
    Title => "Crystal structure of a catalytic intermediate of the mal
+tose transporter",
    Producer => "Acrobat Distiller 6.0.1 (Windows)",
    Cpyrt => " 2007 XXX Publishing Group",
    Identifier => "10.1038/XXX06264",
    EIssn => "1476-4687",
    EndingPage => "521",

<<<SNIP>>>

);

<<<SNIP>>>

my $exifTool = new Image::ExifTool ':Public';
$exifTool->SetNewValue();

for my $Author (@PDFAuthors) {
    ($success, $errStr) = $exifTool->SetNewValue('Creator'=> $Author, 
+AddValue => 1);

    #print "Success: $success\n";
    #print "Error $errStr\n";
}

for my $Attribute (keys %StdPDFattrs) {
    $exifTool->SetNewValue( $Attribute, $StdPDFattrs{$Attribute} );
}

<<<SNIP>>>
[download]

One last suggestion--Don't blindly double-space all your code. Whitespace has a single function: to make the program easy to read/understand. So use indentation and whitespace to make program structure clear.

Good luck with your problem!

...roboticus

P.S. As I was editing your code, I notice that you use 'XMP-RDF' in one place and 'XMP' elsewhere, perhaps your problem with XAP vs. XMP might be a consistency issue?

Update: Repaired CPAN link for module Image::ExifTool.

Update: Fixed %StdPDFattrs definition: I had square brackets instead of parenthesis. ++ to moritz for the catch!