diff --git a/ndiff/ndiff b/ndiff/ndiff
index 81560ef98..c936e0367 100755
--- a/ndiff/ndiff
+++ b/ndiff/ndiff
@@ -659,6 +659,21 @@ class NmapContentHandler(xml.sax.handler.ContentHandler):
         return self.element_stack[-1]
 
     def startElement(self, name, attrs):
+        """This method keeps track of element_stack. The real parsing work is
+        done in startElementAux. This is to make it easy for startElementAux to
+        bail out on error."""
+        self.startElementAux(name, attrs)
+
+        self.element_stack.append(name)
+
+    def endElement(self, name):
+        """This method keeps track of element_stack. The real parsing work is
+        done in endElementAux."""
+        self.element_stack.pop()
+
+        self.endElementAux(name)
+
+    def startElementAux(self, name, attrs):
         if name == u"nmaprun":
             assert self.parent_element() == None
             if attrs.has_key(u"start"):
@@ -778,11 +793,7 @@ class NmapContentHandler(xml.sax.handler.ContentHandler):
                 end_timestamp = int(attrs.get(u"time"))
                 self.scan.end_date = datetime.datetime.fromtimestamp(end_timestamp)
 
-        self.element_stack.append(name)
-
-    def endElement(self, name):
-        self.element_stack.pop()
-
+    def endElementAux(self, name):
         if name == u"nmaprun":
             self.scanned_ports = None
         elif name == u"host":