Templating Error

exceptions.AttributeError: 'str' object has no attribute 'local'

Debugging information follows

   1. While evaluating the standard:'context/deadline/field' expression on line 35
      Current variables:
      templates	<roundup.cgi.templating.Templates instance at 0x4057d7cc>
      repeat	<roundup.cgi.PageTemplates.TALES.SafeMapping instance at 0x4057d84c>
      context	<HTMLClass(0x4057d6cc) issue>
      default	<roundup.cgi.PageTemplates.TALES.Default instance at 0x404f7f4c>
      db	<roundup.cgi.templating.HTMLDatabase instance at 0x4058482c>
      utils	<roundup.cgi.templating.utils instance at 0x4057d4ec>
      request	<roundup.cgi.templating.HTMLRequest instance at 0x4055be2c>
      tracker	<module '_roundup_tracker_1' from '/Projects/psp/roundup/site-issues/__init__.pyo'>
      template	<Roundup PageTemplate 'issue.item.html'>
      nothing	None
      config	<module '_roundup_tracker_1.config' from '/Projects/psp/roundup/site-issues/config.pyo'>
      options	{'ok_message': [], 'error_message': ["Error: property deadline: 'xxxxx' is an invalid date ('xxxxx' not a date spec ([yyyy]-[mm]-[dd].[H]H:MM[:SS.SSS][offset]))"]}
      loop	<roundup.cgi.PageTemplates.TALES.SafeMapping instance at 0x4057d84c>
      notresolved	'-1,1,2,3,4,5,6,7,9'
      resolved	'8'
      usedeadline	True
      printable	False
      displayissues	'@sort=-deadline&@group=priority&@columns=id,activity,deadline,title,creator,assignedto,status&'
      asciitext	False
      attrs	{'colspan': '3', 'tal:content': 'structure context/deadline/field'}
      showproducts	0
   2. A problem occurred in your template "issue.item.html".

Full traceback:

Traceback (most recent call last):
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/client.py", line 527, in renderContext
    result = pt.render(self, None, None, **args)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/templating.py", line 246, in render
    getEngine().getContext(c), output, tal=1, strictinsert=0)()
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 154, in __call__
    self.interpret(self.program)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 186, in interpret
    handlers[opcode](self, args)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 525, in do_useMacro
    self.interpret(macro)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 186, in interpret
    handlers[opcode](self, args)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 345, in do_optTag_tal
    self.do_optTag(stuff)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 330, in do_optTag
    return self.no_tag(start, program)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 325, in no_tag
    self.interpret(program)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 186, in interpret
    handlers[opcode](self, args)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 549, in do_defineSlot
    self.interpret(slot)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 186, in interpret
    handlers[opcode](self, args)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 491, in do_condition
    self.interpret(block)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 186, in interpret
    handlers[opcode](self, args)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/TAL/TALInterpreter.py", line 432, in do_insertStructure_tal
    structure = self.engine.evaluateStructure(expr)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/PageTemplates/TALES.py", line 226, in evaluate
    v = expression(self)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/PageTemplates/Expressions.py", line 189, in __call__
    return self._eval(econtext)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/PageTemplates/Expressions.py", line 184, in _eval
    return render(ob, econtext.vars)
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/PageTemplates/Expressions.py", line 90, in render
    ob = ob()
  File "/Projects/psp/roundup/roundup-0.7.5/lib/python2.3/site-packages/roundup/cgi/templating.py", line 1314, in field
    value = cgi.escape(str(self._value.local(tz)))
AttributeError: 'str' object has no attribute 'local'