The event numbers of error events are given in histograms available online and in the full histogram output file from Tier0. These need to be viewed with the 'text' display option. If the number is too big to be displayed fully enter this ROOT command:

gStyle->SetPaintTextFormat("10.0f")

To find the file the event is in one option is to use the script findEventFile which can be found in the scripts directory of TrigT1CaloMonitoringTools. This works by finding the file GUID in the relevant TAG file and then matching that to a filename in the Grid catalog using dq2-ls. If necessary it will try to download the TAG files from the Grid and can optionally download the resulting RAW or ESD file. If the TAG files are not available on the Grid you can retrieve them from CERN Castor first if you have permission (the l1ccalib account can do it).