Bump. I’m seeing these notices as well.
I’ve fixed the issue in my personal plugin download with the code update below (lines 1045 – 1057 in visual-editor-custom-buttons.php, line 1046 added & line 1050 updated), but the next time you update the plugin, please resolve so the notices don’t appear again. Thank you.
$loop = new WP_Query( $args );
$count = 0;
while ( $loop->have_posts() ) : $loop->the_post();
$custom = get_post_custom(get_the_ID());
$left_tag = $custom["left_tag"][0];
$right_tag = $custom["right_tag"][0];
$quicktag = $custom["quicktag"][0];
$html = $custom["html_editor"][0];
$radio = $custom["content-type"][0];
$block_content = $custom["block_content"][0];
$count++;
