User report - traceback

Hi Univention Forum Reader.

I have a problem at one customer, who wants to use the user reports in the UMC Users module.
When trying to generate the report we get the following traceback:

Interner Server-Fehler in "udm/reports/create (users/user)".
Request: udm/reports/create (users/user)

  File "/usr/lib/python2.7/dist-packages/notifier/threads.py", line 80, in _run
    result = self._function()
  File "/usr/lib/python2.7/dist-packages/notifier/__init__.py", line 104, in __call__
    return self._function(*tmp, **self._kwargs)
  File "/usr/lib/python2.7/dist-packages/univention/management/console/modules/udm/udm_ldap.py", line 97, in _decorated
    return method(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/univention/management/console/ldap.py", line 143, in _decorated
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/univention/management/console/modules/udm/__init__.py", line 661, in _thread
    report_file = report.create(request.flavor, request.options['report'], request.options['objects'])
  File "/usr/lib/python2.7/dist-packages/univention/directory/reports/report.py", line 73, in create
    pdffile = func(tmpfile)
  File "/usr/lib/python2.7/dist-packages/univention/directory/reports/document.py", line 163, in create_rml_pdf
    outputfile = trml2pdf.parseString(fd.read(), output)
  File "/usr/lib/python2.7/dist-packages/trml2pdf/trml2pdf.py", line 539, in parseString
    r.render(fp)
  File "/usr/lib/python2.7/dist-packages/trml2pdf/trml2pdf.py", line 172, in render
    pt_obj.render(self.dom.documentElement.getElementsByTagName('story')[0])
  File "/usr/lib/python2.7/dist-packages/trml2pdf/trml2pdf.py", line 533, in render
    self.doc_tmpl.build(fis)
  File "/usr/lib/python2.7/dist-packages/reportlab/platypus/doctemplate.py", line 956, in build
    self.handle_flowable(flowables)
  File "/usr/lib/python2.7/dist-packages/reportlab/platypus/doctemplate.py", line 851, in handle_flowable
    raise LayoutError(ident)
LayoutError: Flowable <Table@0x7F84986686C8 1 rows x 2 cols(tallest row 747)> with cell(0,0) containing
"<Table@0x7F849850E908 9 rows x 2 cols(tallest row 28)> with cell(0,0) containing\nu'<Paragraph at 0x7f8498508200>Benutzereinzelnachweis: surname givenname'"(442.204724409 x 747.039370079), tallest cell 747.0 points,  too large on page 3 in frame None(441.543307087 x 682.488188976*) of template 'regularpages'

We get this traceback only on a report for one specific user. We have no problems to create reports for all other users.
Can someone tell me what this layout error means?

Kind regards
Basti