Why does "DB2 Recovery Expert" web console doesn't enable the Run and Next button?
The reason could be that the tool identified that there's some information missing. Still in my case everything was there. So, I've found that the solution for my issue was just because, even if you don't have an alternative path for logs or backups, you still have to specify them when running these operations. 

Sometimes even doing so they might not enable instantly. You must go "Previous" and then "Next" to make the web console notice the changes.