Error printing reports that include images

In last version of trunk there is an error in the report printing system when the report includes images of an object.

For example, install "membership_card" module of addons_extra, go to partner and try to print a "Membership card" (it prints like a VISA card with name, code and photo of the partner).

The error is (it does not matter if a photo has added or not to the partner):

Traceback (most recent call last):
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/service/web_services.py", line 585, in go
    (result, format) = obj.create(cr, uid, ids, datas, context)
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/report_sxw.py", line 628, in create
    return self.create_single(cr, uid, ids, data, report_xml, context)
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/report_sxw.py", line 718, in create_single
    pdf = create_doc(rml2, logo, title.encode('utf8'))
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/interface.py", line 198, in create_pdf
    obj.render()
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/render/render.py", line 50, in render
    result = self._render()
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/render/rml.py", line 36, in _render
    return rml2pdf.parseString(self.xml, images=self.bin_datas, path=self.path,title=self.title)
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/render/rml2pdf/trml2pdf.py", line 801, in parseString
    r.render(fp)
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/render/rml2pdf/trml2pdf.py", line 226, in render
    pt_obj.render(self.dom.documentElement.getElementsByTagName('story'))
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/render/rml2pdf/trml2pdf.py", line 783, in render
    fis += r.render(node_story)
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/render/rml2pdf/trml2pdf.py", line 711, in render
    flow = self._flowable(node)
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/render/rml2pdf/trml2pdf.py", line 628, in _flowable
    return self._table(node)
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/render/rml2pdf/trml2pdf.py", line 529, in _table
    fl = self._flowable(n, extra_style=paraStyle)
  File "/home/zikzak/tinyerp/lp-openerp/server/bin/report/render/rml2pdf/trml2pdf.py", line 646, in _flowable
    return platypus.Image(image, mask=(250,255,250,255,250,255), **(utils.attr_get(node, ['width','height'])))
  File "/usr/lib/python2.5/site-packages/reportlab/platypus/flowables.py", line 331, in __init__
    self._setup(width,height,kind,0)
  File "/usr/lib/python2.5/site-packages/reportlab/platypus/flowables.py", line 340, in _setup
    if lazy<=0: self._setup_inner()
  File "/usr/lib/python2.5/site-packages/reportlab/platypus/flowables.py", line 346, in _setup_inner
    img = self._img
  File "/usr/lib/python2.5/site-packages/reportlab/platypus/flowables.py", line 363, in __getattr__
    self._img = ImageReader(self._file)
  File "/usr/lib/python2.5/site-packages/reportlab/lib/utils.py", line 561, in __init__
    a = str(ev.args[-1])+(' fileName='+fileName)
TypeError: cannot concatenate 'str' and 'instance' objects