The process of cleaning my openerp database is taking place.Almost all the modules have been cleared.But now when I click on Customer Refunds in Accounting/Customers/Customer Refunds,I get the following error.

OpenERP Server Error
Client Traceback (most recent call last):
  File "/opt/openerp/server/openerp/addons/web/http.py", line 204, in dispatch
    response["result"] = method(self, **self.params)
  File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 1051, in search_read
    return self.do_search_read(req, model, fields, offset, limit, domain, sort)
  File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 1086, in do_search_read
    records = Model.read(ids, fields or False, req.context)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 42, in proxy
    result = self.proxy.execute_kw(self.session._db, self.session._uid, self.session._password, self.model, method, args, kw)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 30, in proxy_method
    result = self.session.send(self.service_name, method, *args)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 103, in send
    raise xmlrpclib.Fault(openerp.tools.ustr(e), formatted_info)

Server Traceback (most recent call last):
  File "/opt/openerp/server/openerp/addons/web/session.py", line 89, in send
    return openerp.netsvc.dispatch_rpc(service_name, method, args)
  File "/opt/openerp/server/openerp/netsvc.py", line 292, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/opt/openerp/server/openerp/service/web_services.py", line 626, in dispatch
    res = fn(db, uid, *params)
  File "/opt/openerp/server/openerp/osv/osv.py", line 190, in execute_kw
    return self.execute(db, uid, obj, method, *args, **kw or {})
  File "/opt/openerp/server/openerp/osv/osv.py", line 132, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/opt/openerp/server/openerp/osv/osv.py", line 199, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/opt/openerp/server/openerp/osv/osv.py", line 187, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/opt/openerp/server/openerp/osv/orm.py", line 3625, in read
    result = self._read_flat(cr, user, select, fields, context, load)
  File "/opt/openerp/server/openerp/osv/orm.py", line 3746, in _read_flat
    res2 = self._columns[f].get(cr, self, ids, f, user, context=context, values=res)
  File "/opt/openerp/server/openerp/osv/fields.py", line 1142, in get
    result = self._fnct(obj, cr, uid, ids, name, self._arg, context)
  File "/opt/openerp/server/openerp/osv/fields.py", line 1208, in _fnct_read
    value = value[field] or False
  File "/opt/openerp/server/openerp/osv/orm.py", line 405, in __getitem__
    field_values = self._table.read(self._cr, self._uid, ids, field_names, context=self._context, load="_classic_write")
  File "/opt/openerp/server/openerp/osv/orm.py", line 3625, in read
    result = self._read_flat(cr, user, select, fields, context, load)
  File "/opt/openerp/server/openerp/osv/orm.py", line 3746, in _read_flat
    res2 = self._columns[f].get(cr, self, ids, f, user, context=context, values=res)
  File "/opt/openerp/server/openerp/osv/fields.py", line 1142, in get
    result = self._fnct(obj, cr, uid, ids, name, self._arg, context)
  File "/opt/openerp/server/openerp/addons/base/res/res_partner.py", line 212, in <lambda>
    _commercial_partner_id = lambda self, *args, **kwargs: self._commercial_partner_compute(*args, **kwargs)
  File "/opt/openerp/server/openerp/addons/base/res/res_partner.py", line 206, in _commercial_partner_compute
    while not current_partner.is_company and current_partner.parent_id:
  File "/opt/openerp/server/openerp/osv/orm.py", line 499, in __getattr__
    raise AttributeError(e)
AttributeError: 'Unknown attribute is_company in browse_record(res.partner, 379) '.

and i am not able to trace the root cause of the error.Somebody please help me to trace it out.