I try to install some extra addons, but I get always the same error related to a missing external ID

File "/usr/lib/pymodules/python2.7/openerp/addons/base/ir/ir_model.py", line 862, in _get_id raise ValueError('No such external ID currently defined in the system: %s.%s' % (module, xml_id)) ValueError: No such external ID currently defined in the system: stock.warehouse0

Some internet sources explained to update the sales module

after this, I tried to update the warehouse management module

but then I always get the following error :

AssertionError: The report "report.sale.order" already exists!

Does somebody know how I can get out of this problem? I have the fleet management module installed and heavily modified to be used as an aircraft fleet management module. I would not like to loose all these modifications, mainly re-assingnment of fields and modifications in the translations