You got to do something with the license.
I have an unlimited license and have installed the script (v.5.1.1) 4 times, 3 installation in 3 subdomains from 1 domain and 1 in another domain.
Almost of the time I cannot access the admin.
The only solution I got is to take another license number and put it in the key, then it's working, but I cannot use it that way.

I know that these problems comes from the fact that I changed hosting company (IP), and next week I got another server for the other domain, so it's going to be the same.
You should get the hostname, not the subdomain and of course not the Ip.

ps: in the function SEOReplace, please add the "?", otherwise the page is going 404.