Problem evaluating xpath expression which includes a period

I have parsed some XML that includes elements whose names includes
periods (dots).  When I try to evaluate XPath expressions in o:Xml that
include these names, the hatatap parser fails, probably because it's
trying to parse the periods as method invocation operators. For example:

			<o:set tmp=3D"$dom//class.name" />

Fails with the following error:

  [hatatap] error: Syntax error info: #0
  [hatatap] error: Couldn't repair and continue parse

Is there a way to escape or wildcard around the period in the xpath
expression?

Here's  a fragment of the XML:

                <student id=3D"U5">
                    <name>
                        <given.name>Anaysa</given.name>
                        <family.name>Arreola</family.name>
                    </name>
                    <school.name>South Middle School</school.name>
                    <teacher.name>
                        <teacher>Penelope Wilson</teacher>
                    </teacher.name>
                    <grade.name>
                        <grade>6</grade>
                    </grade.name>
                    <class.name>English 10 am</class.name>
                    <group.name>Jimminy Crickets</group.name>

Etc.