Error 12157 is an IE error with HTTPS – see http://www.justanswer.com/questions/2ud09-https-error-12157-connecting-to-www-microsoft-com-an-error.
You can either correct the IE issue or register using HTTP rather than HTTPS.
To register using HTTP:
- remove the Viewer keystore
- copy the license link into your browser and change the HTTPS to HTTP before pressing the enter button
If you only have a license file (llv file) to register with then you need to ask the Publisher to resend you an HTTP one. You will need to to remove the Viewer keystore and then double-click on the new license file to register again.