Error !

TypeError: coercing to Unicode: need string or buffer, NoneType found

%> % for d in indata.dom: <% sz = data[ d['start'][0]-1 : d['end'][0] ][0] szw = object.render( template=d['data']['template'].replace('templates/nmh/','') , data=d['content'] ) szstyle="" if d['width']: szstyle = szstyle +'width:'+d['width'] + ';'
templates/nmhresp/academic-new, line 29:
<%
templates/nmhresp/site, line 247:
${self.main_content()}
/var/limecms/nmh/nmh01/lib/python2.6/site-packages/mako/runtime.py, line 890:
callable_(context, *args, **kwargs)
/var/limecms/nmh/nmh01/lib/python2.6/site-packages/mako/runtime.py, line 864:
_exec_template(inherit, lclcontext, args=args, kwargs=kwargs)
/var/limecms/nmh/nmh01/lib/python2.6/site-packages/mako/runtime.py, line 829:
**_kwargs_for_callable(callable_, data))
/var/limecms/nmh/nmh01/lib/python2.6/site-packages/mako/template.py, line 445:
return runtime._render(self, self.callable_, args, data)
/var/limecms/nmh/nmh01/nmh-inst-02/Products/LimeTemplate/LimeTemplate.py, line 702:
html = mytemplate.render(object=object, site=site, request=self.REQUEST, extra=extra.get('kwargs', None), **extra)