Thanks for pointing me in the right direction!
i’m using the Revelation theme…and I also had to make the following changes to make it work again:
For anyone receiving the wpdb::prepare() error, add this content to your wp-config.php file at the very bottom:
ini_set( ‘display_errors’, false ); error_reporting( 0 );
Then, replace line 51 in /lib/theme-sidebars.php with this:
$widgetized_pages = $wpdb->get_col(“SELECT DISTINCT meta_value FROM $wpdb->postmeta WHERE meta_key = ‘jw_sidebar'”);
That fixed the error messages for me and allowed me to access both the website and the admin area.