Any time it parses anything that has "xmlns:xml" defined, it spits out
an error saying you MUST NOT redefine this attribute. However,
according to the XML spec:

  The prefix xml is by definition bound to the namespace name
  http://www.w3.org/XML/1998/namespace. It MAY, but need not, be
  declared, and MUST NOT be bound to any other namespace name. Other
  prefixes MUST NOT be bound to this namespace name, and it MUST NOT be
  declared as the default namespace.

In other words, it MAY be defined as
http://www.w3.org/XML/1998/namespace. REXML doesn't check to see what
it's defined as, it just dies anytime it sees it defined.

--
Eric Will