You should use strict;. That way, Perl would tell you that you are missing quotes in your construction call to CAM::PDF->new:

# my $pdf = CAM::PDF->new(test.pdf); 
# should be
my $pdf = CAM::PDF->new("test.pdf");
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But you never check whether your call to CAM::PDF->new is successful, so you should do that as well:

my $pdf = CAM::PDF->new("test.pdf")
    or die "Couldn't read PDF 'test.pdf'";
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