Error during Conversion Table loading

Traceback (most recent call last):
  File "/c7/home/fallain/Projects/ariaec/src/ariaec/src/aria/core/AriaXML.py", line 301, in __load
    doc = XMLPickler.load(self, filename, gzip)
  File "/c7/home/fallain/Projects/ariaec/src/ariaec/src/aria/core/xmlutils.py", line 464, in load
    parser.ParseFile(f)
  File "/c7/home/fallain/Projects/ariaec/src/ariaec/src/aria/core/xmlutils.py", line 292, in endElementHandler
    e = self.load_from_element(name, self.current)
  File "/c7/home/fallain/Projects/ariaec/src/ariaec/src/aria/core/AriaXML.py", line 239, in load_from_element
    return pickler.load_from_element(e)
  File "/c7/home/fallain/Projects/ariaec/src/ariaec/src/aria/core/Topology.py", line 390, in load_from_element
    x = AtomGroupXMLPickler.load_from_element(self, e)
  File "/c7/home/fallain/Projects/ariaec/src/ariaec/src/aria/core/Topology.py", line 321, in load_from_element
    if safe_elt(e, 'atom_name'):
  File "/c7/home/fallain/Projects/ariaec/src/ariaec/src/aria/core/xmlutils.py", line 133, in __getattr__
    raise XMLTagError(name)
XMLTagError: XML tag "atom_name.__nonzero__" not known or missing.

ERROR    [AriaXMLPickler]: File "/c7/home/fallain/Projects/ariaec/src/ariaec/src/
                           aria/core/AriaXML.py", line 336 in load
                           XML file /c7/home/fallain/Projects/ariaec/src/ariaec/
                           src/aria/data/iupac.xml: XML tag "atom_name.__nonzero_
                           _" not known or missing.
                           Make sure that all tags/attributes are spelled 
                           correctly and that no mandatory tags/attributes are 
                           missing.