If you have yet to discover which version of libxml is installed I suggest you speak to your systems administrator, keeping in mind what Tux as told you.

Don't bother the nice administrator with stuff you can find out yourself

$ perldoc XML::LibXML |grep -in version
10:      $Version_String = XML::LibXML::LIBXML_DOTTED_VERSION;
11:      $Version_ID = XML::LibXML::LIBXML_VERSION;
12:      $DLL_Version = XML::LibXML::LIBXML_RUNTIME_VERSION;
[download]

use XML::LibXML;
print join "\n", XML::LibXML::LIBXML_DOTTED_VERSION(),
XML::LibXML::LIBXML_VERSION(),
XML::LibXML::LIBXML_RUNTIME_VERSION(),
$XML::LibXML::VERSION,
"";
__END__
2.9.0
20900
20900
2.0014
[download]