HI There,
I have a complete mongo infrastructure running on mongo 2.2.2 version.
Now i am going to upgrade it to 2.4.6.
After stopping the balancer on an existing mongos (using sh.setBalancerState(false)),
I started a new mongos instance with --upgrade parameter, but it is giving me error below:
Wed Oct 30 09:08:56.405 [mongosMain] ERROR: error upgrading config database to v4 :: caused by :: balancer must be stopped for config upgrade

I connected to already running mongos and checked sh.getBalancerState(), which returned true
and db.locks.find()
which showed that nothing was locked and new mongos should be able to run. The complete output of locks is:
{ "_id" : "abc.def", "process" : "mh-ewr-p06:27018:1382962411:31791660", "state" : 0, "ts" : ObjectId("526eb19f6eb306496fcbcde5"), "when" : ISODate("2013-10-28T18:49:03.811Z"), "who" : "mh-ewr-p06:27018:1382962411:31791660:conn1192:1891349643", "why" : "migrate-

{ rcode: \"67CII0506453R59XJ3247P47\" }

" }
{ "_id" : "abc.xyz", "process" : "mh-ewr-p06:27017:1382964236:1618003131", "state" : 0, "ts" : ObjectId("526f52c04860bac76e7635ce"), "when" : ISODate("2013-10-29T06:16:32.136Z"), "who" : "mh-ewr-p06:27017:1382964236:1618003131:conn2602:1216501464", "why" : "migrate-

{ rcode: \"5G692J1H9SBD07NFI7Z0UV64\" }

" }

{ "_id" : "balancer", "process" : "mh-ewr-q39:27017:1382947397:1804289383", "state" : 0, "ts" : ObjectId("5270a6954bc9fe7fafb93bfb"), "when" : ISODate("2013-10-30T06:26:29.678Z"), "who" : "mh-ewr-q39:27017:1382947397:1804289383:Balancer:846930886", "why" : "doing balance round" }

Can somebody please explain me, why still i am getting the error in running a new instance of mongos?
This is blocking my testing of migration, so please help.