Is there any problem with your router?

Two same units in the kit. No worries.

Yep, they are compatible with each other indeed. Did you try to connect PC directly to the router? Is it working? You may try to reset powerline devices and re-pair them....

Before you run the utilty, ensure anti-virus software and firewall are disabled. To log in web interface of WPA4220, there are two methods actually. http://www.tp-link.com/en/faq-398.html

Pair them in the same room first. http://www.tp-link.com/en/faq-258.html

Telephone line or Fibre optic link is connected to the openreach supplied modem for internet access? Without a router, you can access internet directly or not? If it is fibre optic link, you have to...