Hello,

How can I find private key? I used the command "dumpprivkey [public address]" in debug console to view private key in text format, but get nothing but this message:  
09:29:46 dumpprivkey [public address]
09:29:46 dumpprivkey Reveals the private key corresponding to . (code -1)

Also, how to Edit Public/Private key into image? Where can I get an image as well QR code?

For alternative option: how can I link wallet.dat file to QR code?

Thanks!