Fatal error: Call to undefined function wp_enqueue_styles

After updating to ver. 1.1.3, attempts to access the admin section (of six WP sites on which the plugin was installed – four on WP 3.5 and two on WP 3.4.2) results in the following error:

Fatal error: Call to undefined function wp_enqueue_styles() in /home/[site path]/plugins/custom-login/custom-login.php on line 168

Removing the plugin from all sites via FTP corrected the issue.

http://wordpress.org/extend/plugins/custom-login/