Admin Block Country 1.0 blocked me out of my WP admin page (apparently by changing the ht.acess file). I'm a WP newbie, so I don't have a clear understanding of the issue, but I had to resolve it through my host server. Although I really like the idea of blocking my site from IPs by country, this plug-in was just a headache. I am using WordPress 3.6, and the plug in does not seem to be compatible with this version.
Update: I received a quick response from the developer, who is very helpful. I suspect my problem was either from plug-in (Better WP Security 3.5.5) or theme (Responsive 18.104.22.168) incompatibilities, as I was able to get access to my admin page after deactivating both of these files via my server, as well as Admin Country Block. Once I was in Admin again, I deleted Admin Block Country, deactivated Better WP Security, cleared my .htacess file, reactivated my Responsive theme, refreshed my permalinks and everything was back to normal.