I installed DC-Unlocker program and purchased 7 credits (what was suggested on the purchase page). So I proceeded to the DC-Unlocker website (thinking that the modem had installed new software and was now locked to the Bolt network in Indonesia, and so needed unlocking?). I tried another SIM card, but this ddn't change the status. After the update installed the Modem is now showing 'Device Locked' on the LCD screen. Yesterday it showed an update available on the LCD screen, so I pressed the power button (as instructed) and the modem started downloading the update.
It came unlocked and I have been using it in Australia for 5 months without a problem. I have a E5372s wireless modem that I purchased (new) 6 months ago in Indonesia.