Download the AV Viewer today and archive the installer on three separate drives (one for IT, one for evidence, one offline). Also, convert all critical legacy .dat files to MP4 while you still have a functional viewer.
Panasonic no longer hosts version 1.x or 2.x of the AV Viewer on its public servers. If you have an older Arbitrator unit, you may need to contact support to request a legacy installer. panasonic arbitrator 360 av viewer download