[V5.0] account_payment crash when printing "Payment Order" with no line

Using latest stable branches from LP for v5.0, on a freshly created DB with demo data, I installed the module "account_payment", created an empty payment order (no payment line), try to print the report "Payment Order" and got an error message :
Traceback (most recent call last):
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/service/web_services.py", line 630, in go
    (result, format) = obj.create(cr, uid, ids, datas, context)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/report_sxw.py", line 364, in create
    return fnct(cr, uid, ids, data, report_xml, context)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/report_sxw.py", line 421, in create_source_pdf
    return self.create_single_pdf(cr, uid, ids, data, report_xml, context)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/report_sxw.py", line 437, in create_single_pdf
    pdf = create_doc(etree.tostring(processed_rml),rml_parser.localcontext,logo,title.encode('utf8'))
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/interface.py", line 199, in create_pdf
    obj.render()
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/render/render.py", line 50, in render
    result = self._render()
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/render/rml.py", line 41, in _render
    return rml2pdf.parseNode(self.rml, self.localcontext, images=self.bin_datas, path=self.path,title=self.title)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/render/rml2pdf/trml2pdf.py", line 776, in parseNode
    r.render(fp)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/render/rml2pdf/trml2pdf.py", line 195, in render
    pt_obj.render(el)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/render/rml2pdf/trml2pdf.py", line 764, in render
    fis += r.render(node_story)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/render/rml2pdf/trml2pdf.py", line 696, in render
    return process_story(node_story)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/render/rml2pdf/trml2pdf.py", line 689, in process_story
    flow = self._flowable(node)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/render/rml2pdf/trml2pdf.py", line 603, in _flowable
    return self._table(node)
  File "/home/ls/Projets/OpenERP/v5.0/server/bin/report/render/rml2pdf/trml2pdf.py", line 521, in _table
    assert length == len(node.get('colWidths').split(','))
AssertionError