Errors creating drop down lists - stops customisation

When editing the res.partners.contact object within the web client or gtk client, the below error occurs. However this only seems to occur after adding a selection field within any selection values example being the default []. I expect an error like that, however if you go back to edit the same field, enter some values like [('select1','select1')], saving the object re produces the same error. Checking all fields with selection a\s the type, making sure all have values to select, does not make any difference. Upgrading to the latest version does not resolve this.

Environment Information :
System : Windows-Vista-6.1.7600
OS Name : nt
Operating System Release : Vista
Operating System Version : 6.1.7600
Operating System Architecture : 32bit
Operating System Locale : en_GB.cp1252
Python Version : 2.5.2
OpenERP-Client Version : 5.0.12
Last revision No. & ID :Bazaar Package not Found !Traceback (most recent call last):
  File "/usr/lib/python2.5/site-packages/openerp-server/netsvc.py", line 247, in dispatch
    result = LocalService(service_name)(method, *params)
  File "/usr/lib/python2.5/site-packages/openerp-server/netsvc.py", line 76, in __call__
    return getattr(self, method)(*params)
  File "/usr/lib/python2.5/site-packages/openerp-server/service/web_services.py", line 577, in execute
    res = service.execute(db, uid, object, method, *args)
  File "/usr/lib/python2.5/site-packages/openerp-server/osv/osv.py", line 58, in wrapper
    return f(self, dbname, *args, **kwargs)
  File "/usr/lib/python2.5/site-packages/openerp-server/osv/osv.py", line 119, in execute
    res = pool.execute_cr(cr, uid, obj, method, *args, **kw)
  File "/usr/lib/python2.5/site-packages/openerp-server/osv/osv.py", line 111, in execute_cr
    return getattr(object, method)(cr, uid, *args, **kw)
  File "/usr/lib/python2.5/site-packages/openerp-server/addons/base/ir/ir_model.py", line 77, in write
    return super(ir_model,self).write(cr, user, ids, vals, context)
  File "/usr/lib/python2.5/site-packages/openerp-server/osv/orm.py", line 2659, in write
    result += self._columns[field].set(cr, self, id, field, vals[field], user, context=rel_context) or []
  File "/usr/lib/python2.5/site-packages/openerp-server/osv/fields.py", line 445, in set
    id_new = obj.create(cr, user, act[2], context=context)
  File "/usr/lib/python2.5/site-packages/openerp-server/addons/base/ir/ir_model.py", line 271, in create
    self.pool.get(vals['model'])._auto_init(cr, ctx)
  File "/usr/lib/python2.5/site-packages/openerp-server/osv/orm.py", line 1885, in _auto_init
    f_obj_type = get_pg_type(f) and get_pg_type(f)[0]
  File "/usr/lib/python2.5/site-packages/openerp-server/osv/orm.py", line 297, in get_pg_type
    if isinstance(f.selection, list) and isinstance(f.selection[0][0], (str, unicode)):
IndexError: list index out of range