Hyphenated nodeName or DTD nested in XML causes Feeds XPath Parser failure
There are 2 errors regarding the xml:id and xsi:schemaLocation, but they are not fatal. I'm guessing the xsi namespace is defined previously.

There's nothing wrong with nested namespaces.

Is there a default namespace declare somewhere passed the root? That could be because of https://drupal.org/node/1220834.

The hyphen in EAC-CPF is not causing the problems.

Remember that if elements have a namepsace, the namespace must be present in the XPath query.