Hi,
I too had the same problem. Great plugin and realy wanted to use it for my latest project so after reading above I decided to look into it for you.
Carry out the changes mentioned above, changing the two links will get you onto the settings page.
Now to get the Modal popup for each order working on the Orders list there are two more changes needed.
1. on line 149 change “order_comments” to “order_notes” which was a change woocommerce made in the naming of the column in the orders list.
2. on line 80 you need to change
jQuery('#the-list #post-<?php echo $post->ID; ?>').find('.order_comments a.post-com-count').attr("href", "#TB_inline?width=600&height=550&inlineId=order-notes-<?php echo $post->ID; ?>").addClass("thickbox");
to
var notes_link = '<a class="thickbox" href="#TB_inline?width=600&height=550&inlineId=order-notes-<?php echo $post->ID; ?>">Notes</a>';
jQuery('#the-list #post-<?php echo $post->ID; ?>').find('.order_notes span').after(notes_link);
This simply injects an extra anchor link which will open the modal.
Hope that helps someone too.
Kind Regards
Philip C