Why does Preupgrade package install fail with error "Depsolving loop limit reached" and preupg runtime error "not well-formed (invalid token) line 7200, column 42" ?

Issue

• When installing the preupgrade package after having installed a Red Hat Enterprise Linux 7 local repository (ISO image) as described in §1.4 "Consider other repositories" and §2.2 "Install the preupgrade package" in the article, the installation stops with the error message "Depsolving loop limit reached" and an error list of 1115 lines

# yum -y install preupgrade-assistant preupgrade-assistant-ui preupgrade-assistant-contents

• After recovering a snapshot and retry in the opposite order, by installing the preupgrade package before installing the Red Hat Enterprise Linux 7 repo, the installation of the preupgrade package succeeded.
• The order of those two might be wrong since the installation looks at the Red Hat Enterprise Linux 7 repo, making the dependency list too long
• Further more, running preupg results in an error:

   Usage: preupg [options]

   preupg: error: not well-formed (invalid token): line 7200, column 42

• preupg Traceback:

Traceback (most recent call last):
  File "/usr/bin/preupg", line 33, in <module>
    sys.exit(main())
  File "/usr/bin/preupg", line 20, in main
    ret = app.run()
  File "/usr/lib/python2.6/site-packages/preup/application.py", line 673, in run
    tarball_path = self.scan_system()
  File "/usr/lib/python2.6/site-packages/preup/application.py", line 516, in scan_system
    self.prepare_xml_for_html()
  File "/usr/lib/python2.6/site-packages/preup/application.py", line 368, in prepare_xml_for_html
    self.report_parser.reload_xml(self.get_default_xml_result_path())
  File "/usr/lib/python2.6/site-packages/preup/report_parser.py", line 138, in reload_xml
    self.target_tree = ElementTree.fromstring(content)
  File "/usr/lib64/python2.6/xml/etree/ElementTree.py", line 963, in XML
    parser.feed(text)
  File "/usr/lib64/python2.6/xml/etree/ElementTree.py", line 1245, in feed
    self._parser.Parse(data, 0)
xml.parsers.expat.ExpatError: not well-formed (invalid token): line 7200, column 42