Custom Contact Forms broken

Since upgrading to 4.5.3.0, the following message appears on top of all wp-admin pages. It also appears in some widgets on the dashboard.

Warning: array_shift() [function.array-shift]: The argument should be an array in /wp-content/plugins/custom-contact-forms/modules/widget/custom-contact-forms-dashboard.php on line 22

The following page provided a fix: https://www.ads-software.com/support/topic/how-to-solve-array_shift-warning

Further more, the widget on the dashboard disappeared; when attempting to make it visible to all users except subscribers, I was presented with another error and no way to access the admin panel.

Fatal error: Call to a member function get_names() on a non-object in /wp-content/plugins/custom-contact-forms/modules/db/custom-contact-forms-db.php on line 401

I have had to rename the plugin folder to force WP to disable the plugin.

Adding the following before the call to get_names() seems to resolve the problem:

if ( ! isset( $wp_roles ) ) {
    $wp_roles = new WP_Roles();
}