nested conditional to check for feature image and custom field?

I believe this should do what you want:

<?php
if ( has_post_thumbnail() ) {
    echo '<div id="venue-single-img">';
    the_post_thumbnail();
    if ( get_post_meta($post->ID, 'Venue Image Notation', true) ) {
        echo '<span>' . get_post_meta($post->ID, 'Venue Image Notation', true) . '</span>';
    }
    echo '</div>';
}
?>

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)