@subramanin sounds like your BR player has gone into power protect mode. When that happens you pretty much cannot access anything on your player until the error is cleared. Try a rest first. For a reset remove everything that is plugged in to it and let it sit for an hour or so. Now, I am not familiar with your model so I can not tell you if there is a reset button. Some Sony's have a reset button or a reset hole (insert a paperclip into that and hold for 15-30 sec to reset).
ALways make sure that everything plugged in makes proper connection and check your power cord etc. If a reset does not work and it continues to display the message, it may be time to disassemble it and check the power supply etc.