I had the same issue. What worked for me was loading a fresh clean install of Windows XP on a laptop with no updates and plugged straight into the router RB2011. After trying Netinstall that way; the install button worked for me. Before that; it was doing the same thing you describe when clicking install.
Sorry, I forgot that there was another variable I had tried; a different version of NetInstall. At first I was using 6.42.5 and it wasn’t working then I tried with 6.40.8 and it worked along with the above.
Try plugging a switch between the computer and router board. Firewall off. Set a static ip on your computer. That’s how i usually do it with windows 10 and it works.