The file /home/mysite.net/public_html/extensions/plugins/bulletproof-security/admin/htaccess/secure.htaccess is not writable or does not exist.
Check that the file is named secure.htaccess and that the file exists in the /bulletproof-security/admin/htaccess master folder. If this is not the problem click here for more help info.
I have the following in my wp-config.php file (which is accepted practice for WP)
/* Custom Paths */ define( 'WP_CONTENT_DIR', $_SERVER['DOCUMENT_ROOT'] . '/extensions' ); define( 'WP_CONTENT_URL', 'http://mysite.net/extensions'); define( 'WP_PLUGIN_DIR', $_SERVER['DOCUMENT_ROOT'] . '/extensions/addons' ); define( 'WP_PLUGIN_URL', 'http://mysite.net/extensions/addons'); define( 'PLUGINDIR', $_SERVER['DOCUMENT_ROOT'] . '/extensions/addons' );
Basically I can't use the plugin because you are assuming that the plugin directory is named plugins. I haven't gotten further in your plugin to see if there are going to be other issues as well due to this.
The WP docs basically say to never assume any of the names wp-content, plugins, etc. Hope it helps for next release.