--- a/lib/PDF/API2/Basic/PDF/File.pm	2017-01-26 10:30:03.000000000 -0800
+++ b/lib/PDF/API2/Basic/PDF/File.pm	2017-06-21 16:33:17.000000000 -0700
@@ -1273,7 +1273,7 @@
     my $tloc = $fh->tell();
     $fh->print("xref\n");
 
-    my @xreflist = sort { $self->{' objects'}{$a->uid}[0] <=> $self->{' objects'}{$b->uid}[0] } (@{$self->{' printed'}}, @{$self->{' free'}});
+    my @xreflist = sort { $self->{' objects'}{$a->uid}[0] <=> $self->{' objects'}{$b->uid}[0] } (@{$self->{' printed'}||[]}, @{$self->{' free'}||[]});
 
     my ($i, $j, $k);
     unless ($update) {
@@ -1294,7 +1294,7 @@
         }
     }
 
-    my @freelist = sort { $self->{' objects'}{$a->uid}[0] <=> $self->{' objects'}{$b->uid}[0] } @{$self->{' free'}};
+    my @freelist = sort { $self->{' objects'}{$a->uid}[0] <=> $self->{' objects'}{$b->uid}[0] } @{$self->{' free'}||[]};
 
     $j = 0; my $first = -1; $k = 0;
     for ($i = 0; $i <= $#xreflist + 1; $i++) {