Error creating a DTA

We encountered the following error with the version 6.0.0 of OpenERP-Server:

Environment Information :
System : Windows-32bit
OS Name : nt
Operating System Release :
Operating System Version : 32bit
Operating System Architecture : 32bit
Operating System Locale : fr_CH.cp1252
Python Version : 2.5.2
OpenERP-Client Version : 6.0.0-rc2
Last revision No. & ID :Bazaar Package not Found !Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/openerp-server/netsvc.py", line 489, in dispatch
    result = ExportService.getService(service_name).dispatch(method, auth, params)
  File "/usr/local/lib/python2.6/dist-packages/openerp-server/service/web_services.py", line 599, in dispatch
    res = fn(db, uid, *params)
  File "/usr/local/lib/python2.6/dist-packages/openerp-server/osv/osv.py", line 122, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/openerp-server/osv/osv.py", line 176, in execute
    res = self.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/usr/local/lib/python2.6/dist-packages/openerp-server/osv/osv.py", line 167, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/usr/local/lib/python2.6/dist-packages/openerp-server/addons/l10n_ch/wizard/create_dta.py", line 582, in create_dta
    dta_file = _create_dta(self, cr, uid, data, context)
  File "/usr/local/lib/python2.6/dist-packages/openerp-server/addons/l10n_ch/wizard/create_dta.py", line 557, in _create_dta
    payment_obj.set_done(cr, uid, data['id'], context)
  File "/usr/local/lib/python2.6/dist-packages/openerp-server/addons/account_payment/account_payment.py", line 126, in set_done
    wf_service.trg_validate(uid, 'payment.order', ids[0], 'done', cr)
TypeError: 'int' object is unsubscriptable

This happened while confirming that we wanted to create a DTA file using the corresponding wizard in l10n_ch .
This happened with a new payment order to a supplier (bank details: DTA-BVRBANK)
The company's partner which wants to pay is using: "Ordering party DTA

Best regards