Corrected => Trying to get property of non-object

Corrected Notices:
Notice: Trying to get property of non-object in video-embed-thumbnail-generator.php on line 4421
Notice: Trying to get property of non-object in video-embed-thumbnail-generator.php on line 4365
Notice: Trying to get property of non-object in video-embed-thumbnail-generator.php on line 4366
Notice: Trying to get property of non-object in video-embed-thumbnail-generator.php on line 4371