Is there a .maintenance file in your WordPress directory? This file automatically goes up when there is a problem in the WP Admin. Take a look, see if that may be causing your problem. 🙂
For future reference, just rename the plugin folder and that will deactivate the plugin. Then, from within the WP-Admin you can delete it.
You shouldn’t need to edit your wp-config file, as the installer will do this for you if the permissions are set up correctly.
This can also be due to something in your .htaccess file in your WordPress directory & root directory. You can try renaming this file to see if it resolves your problem.
Let me know if that helps. 🙂
