i have v8 and v9 on the same computer odoo v9 is  working fine when i'm running odoo v8  i got this error in the log file 

  File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 177, in run_wsgi

 execute(self.server.app)

File "/usr/local/lib/python2.7/dist-packages/werkzeug/serving.py", line 165, in execute

application_iter = app(environ, start_response)

File "/opt/odoo8/openerp/service/server.py", line 290, in app

return self.app(e, s)

File "/opt/odoo8/openerp/service/wsgi_server.py", line 216, in application

return application_unproxied(environ, start_response)

File "/opt/odoo8/openerp/service/wsgi_server.py", line 202, in application_unproxied

result = handler(environ, start_response)

File "/opt/odoo8/openerp/http.py", line 1290, in __call__

return self.dispatch(environ, start_response)

File "/opt/odoo8/openerp/http.py", line 1264, in __call__

return self.app(environ, start_wrapped)

File "/usr/local/lib/python2.7/dist-packages/werkzeug/wsgi.py", line 588, in __call__

return self.app(environ, start_response)

File "/opt/odoo8/openerp/http.py", line 1437, in dispatch

result = ir_http._dispatch()

File "/opt/odoo8/openerp/addons/base/ir/ir_http.py", line 152, in _dispatch

rule, arguments = self._find_handler(return_rule=True)

File "/opt/odoo8/openerp/addons/base/ir/ir_http.py", line 65, in _find_handler

return self.routing_map().bind_to_environ(request.httprequest.environ).match(return_rule=return_rule)

File "/opt/odoo8/openerp/addons/base/ir/ir_http.py", line 199, in routing_map

self._routing_map = http.routing_map(mods, False, converters=self._get_converters())

File "/opt/odoo8/openerp/http.py", line 856, in routing_map

routing_map.add(werkzeug.routing.Rule(url, endpoint=endpoint, methods=routing['methods'], **kw))

File "/usr/local/lib/python2.7/dist-packages/werkzeug/routing.py", line 1083, in add

rule.bind(self)

File "/usr/local/lib/python2.7/dist-packages/werkzeug/routing.py", line 598, in bind

self.compile()

File "/usr/local/lib/python2.7/dist-packages/werkzeug/routing.py", line 648, in compile

_build_regex(self.is_leaf and self.rule or self.rule.rstrip('/'))

File "/usr/local/lib/python2.7/dist-packages/werkzeug/routing.py", line 638, in _build_regex

variable, converter, c_args, c_kwargs)

File "/usr/local/lib/python2.7/dist-packages/werkzeug/routing.py", line 606, in get_converter

raise LookupError('the converter %r does not exist' % converter_name)

LookupError: the converter 'page' does not exist