i am installing database while got the error

i am installing database while got the error

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Traceback (most recent call last):
  File "/mnt/openerp/server/bin/netsvc.py", line 244, in dispatch
    result = LocalService(service_name)(method, *params)
  File "/mnt/openerp/server/bin/netsvc.py", line 73, in __call__
    return getattr(self, method)(*params)
  File "/mnt/openerp/server/bin/service/web_services.py", line 633, in execute
    return self._execute(db, uid, wiz_id, datas, action, context)
  File "/mnt/openerp/server/bin/service/web_services.py", line 613, in _execute
    return wiz.execute(db, uid, self.wiz_datas[wiz_id], action, context)
  File "/mnt/openerp/server/bin/wizard/__init__.py", line 177, in execute
    res = self.execute_cr(cr, uid, data, state, context)
  File "/mnt/openerp/server/bin/wizard/__init__.py", line 73, in execute_cr
    action_res = action(self, cr, uid, data, context)
  File "/mnt/openerp/server/bin/addons/base_setup/wizard/wizard_base_setup.py", line 205, in _update
    (db, pool)=pooler.restart_pool(cr.dbname, update_module=True)
  File "/mnt/openerp/server/bin/pooler.py", line 62, in restart_pool
    return get_db_and_pool(db_name, force_demo, status, update_module=update_module)
  File "/mnt/openerp/server/bin/pooler.py", line 40, in get_db_and_pool
    addons.load_modules(db, force_demo, status, update_module)
  File "/mnt/openerp/server/bin/addons/__init__.py", line 740, in load_modules
    r = load_module_graph(cr, graph, status, report=report)
  File "/mnt/openerp/server/bin/addons/__init__.py", line 642, in load_module_graph
    tools.convert_xml_import(cr, m, fp, idref, mode=mode, noupdate=True, **kwargs)
  File "/mnt/openerp/server/bin/tools/convert.py", line 853, in convert_xml_import
    obj.parse(doc.getroot())
  File "/mnt/openerp/server/bin/tools/convert.py", line 750, in parse
    self._tags[rec.tag](self.cr, rec, n)
  File "/mnt/openerp/server/bin/tools/convert.py", line 646, in _tag_assert
    raise Exception('Severe assertion failure')
Exception: Severe assertion failure