Description
There are 2 versions of certified data files in
https://cms-service-dqmdc.web.cern.ch/CAF/certification/Collisions11/7TeV/Reprocessing/ :
https://cms-service-dqmdc.web.cern.ch/CAF/certification/Collisions11/7TeV/Reprocessing/Cert_160404-180252_7TeV_ReRecoNov08_Collisions11_JSON.txt
https://cms-service-dqmdc.web.cern.ch/CAF/certification/Collisions11/7TeV/Reprocessing/Cert_160404-180252_7TeV_ReRecoNov08_Collisions11_JSON_MuonPhys.txt
https://cms-service-dqmdc.web.cern.ch/CAF/certification/Collisions11/7TeV/Reprocessing/Cert_160404-180252_7TeV_ReRecoNov08_Collisions11_JSON_MuonPhys_v2.txt
https://cms-service-dqmdc.web.cern.ch/CAF/certification/Collisions11/7TeV/Reprocessing/Cert_160404-180252_7TeV_ReRecoNov08_Collisions11_JSON_v2.txt
The file in http://opendata.cern.ch/record/1001 is the one without v2. Recheck.