diff --git a/mozilla/extensions/psm-glue/res/content/securityOverlay.xul b/mozilla/extensions/psm-glue/res/content/securityOverlay.xul
index ff775edda62..4a4f4409a84 100644
--- a/mozilla/extensions/psm-glue/res/content/securityOverlay.xul
+++ b/mozilla/extensions/psm-glue/res/content/securityOverlay.xul
@@ -4,7 +4,7 @@
 <!DOCTYPE window SYSTEM "chrome://communicator/locale/securityOverlay.dtd">
 
 <overlay id="NavSecurityOverlay"
-         xmlns:html="http://www.w3.org/TR/REC-html40"
+         xmlns:html="http://www.w3.org/1999/xhtml"
          xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
 
   <script language="JavaScript" src="chrome://communicator/content/securityUI.js" />
diff --git a/mozilla/xpfe/communicator/resources/content/dialogBindings.xml b/mozilla/xpfe/communicator/resources/content/dialogBindings.xml
index 440b3ec3bac..b6b6943a09f 100644
--- a/mozilla/xpfe/communicator/resources/content/dialogBindings.xml
+++ b/mozilla/xpfe/communicator/resources/content/dialogBindings.xml
@@ -2,7 +2,7 @@
 
 <bindings id="dialogBindings"
    xmlns="http://www.mozilla.org/xbl"
-   xmlns:html="http://www.w3.org/TR/REC-html40"
+   xmlns:html="http://www.w3.org/1999/xhtml"
    xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
 
   <binding id="smallheader">