Panasonic DMR-E20

Question

Recently, This DVR finds fewer and fewer discs acceptable. It will play Side 1 of Schindlers List beautifully, but will not recognize Side 2. Same for many movies I recorded on it previously and had played well. Now it cannot even recognize blank discs for recording. Some movies I buy it will read, but most not. On occasion I can hear a shutter or gring when I insert a DVD. Help?