It seems to me that you have two versions of libxml2 installed, causing some conflicts for XML::LibXML. You'll need to remove one or correct the path. As for which one to remove, you can check to see which libxml2 XML::LibXML is linked to like this:

#!/usr/bin/perl

use strict;
use warnings;
use XML::LibXML;

print my $DLL_Version = XML::LibXML::LIBXML_RUNTIME_VERSION, "\n";
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It returns 20626 on my machine.