If you believe you have correctly installed the geolocation browser plugin and would like to confirm: PC: Open Control Panel > Programs > Programs and Features.
The Player Location Check plugin should be listed there. Mac: Open system preferences > look for Player Location Check icon in the bottom row of System Preferences window (below Date & Time, Time Machine, etc.).
If it is installed, it will appear here. If the website still cannot detect the plugin, consider uninstalling and reinstalling the Player Location Check plugin.