#!perl -w
use strict;
require Win32::ChangeNotify;

my($dir)= @ARGV;

while(1) {
    $notify = Win32::ChangeNotify->new($dir,0,'FILE_NAME');
    $notify->wait or warn "Something failed: $! / $^E\n";

    sleep 10; # give the process writing the file some time

    for my $pdf (glob "$dir/*.pdf" ) { ; # we process all files here, because I'm lazy
        system(1, qq{"C:\\Program Files (x86)\\Adobe\\Reader 10.0\\Reader\\AcroRd32.exe" /t $pdf});
    };

    $notify->reset();
}