Index: /CKEditor/trunk/_source/core/htmlparser/element.js
===================================================================
--- /CKEditor/trunk/_source/core/htmlparser/element.js	(revision 6437)
+++ /CKEditor/trunk/_source/core/htmlparser/element.js	(revision 6438)
@@ -35,5 +35,5 @@
 	this.children = [];
 
-	var tagName = attributes[ 'data-cke-real-element-type' ] || name;
+	var tagName = attributes[ 'data-cke-real-element-type' ] || name || '';
 
 	// Reveal the real semantic of our internal custom tag name (#6639).