zzz_cuztom_url (youtube) + emthumb = not working?

#1

1. create new node
2. enter video url (custom, youtube)
3. upload custom thumbnail. (emthumb)
4. save the node.

result : video displays without custom thumbnail. but custom thumbnail file's uploaded.

#2.

1. edit existing video node.
2. upload custom thumbnail.
3. save the node.

result : video displays without custom thumbnail. custom thumbnail's NOT uploaded in to server.

#3
default thumbnail is not displaying!

file : emvideo/providers/zzz_custom_url.inc
function : theme_emvideo_zzz_custom_url_embedded_video()
line: ~ #156

      ...
      // Grab the thumbnail for this video and tell JW FLV Player about it.
      $flashvars['image'] = theme('emvideo_video_thumbnail', NULL, $item, 'emvideo_thumbnail', $options['node'], FALSE, $tn_options);
      ...

changed to

      ...
      // Grab the thumbnail for this video and tell JW FLV Player about it.
      $flashvars['image'] = theme('emvideo_video_thumbnail', $field, $item, 'emvideo_thumbnail', $options['node'], TRUE, $tn_options);
      ...

--->
I got default thumbnail image.