Index: editor/_source/internals/fckxhtml.js
===================================================================
--- editor/_source/internals/fckxhtml.js	(revision 5126)
+++ editor/_source/internals/fckxhtml.js	(revision )
@@ -147,7 +147,9 @@
 
 FCKXHtml._AppendChildNodes = function( xmlNode, htmlNode, isBlockElement )
 {
-	var oNode = htmlNode.firstChild ;
+	// Sometimes IE DOM doesn't report the first child node even
+	// if there's a single one exist, e.g. <span><p>text</p></span>.
+	var oNode = htmlNode.firstChild || htmlNode.childNodes.length && htmlNode.lastChild;
 
 	while ( oNode )
 	{