Index: wp-admin/includes/class-wp-media-list-table.php
===================================================================
--- wp-admin/includes/class-wp-media-list-table.php	(revision 27402)
+++ wp-admin/includes/class-wp-media-list-table.php	(working copy)
@@ -329,7 +329,7 @@
 			$parent_type = get_post_type_object( $parent->post_type );
 ?>
 			<td <?php echo $attributes ?>><strong>
-				<?php if ( current_user_can( 'edit_post', $post->post_parent ) && $parent_type->show_ui ) { ?>
+				<?php if ( isset( $parent_type->show_ui ) && current_user_can( 'edit_post', $post->post_parent ) && $parent_type->show_ui ) { ?>
 					<a href="<?php echo get_edit_post_link( $post->post_parent ); ?>">
 						<?php echo $title ?></a><?php
 				} else {