Try registering the smime chrome the right way.....chrome in mail.jst and the locale in

langenus.jst

xpinstall/packager/windows/langenus.jst

@@ -58,6 +58,7 @@ if(verifyDiskSpace(fProgram, srDest))
     registerChrome(chromeType, cf, localeName + "global/");
     registerChrome(chromeType, cf, localeName + "communicator/");
     registerChrome(chromeType, cf, localeName + "messenger/");
+    registerChrome(chromeType, cf, localeName + "messenger-smime/");
     registerChrome(chromeType, cf, localeName + "editor/");
     registerChrome(chromeType, cf, localeName + "navigator/");
     registerChrome(chromeType, cf, localeName + "necko/");

xpinstall/packager/windows/mail.jst

@@ -342,6 +342,9 @@ if(verifyDiskSpace(fProgram, srDest))
     registerChrome(CONTENT | DELAYED_CHROME,
                    getFolder("Chrome","messenger.jar"),
                    "content/messenger-region/");
+    registerChrome(CONTENT | DELAYED_CHROME,
+                   getFolder("Chrome","messenger.jar"),
+                   "content/messenger-smime/");
 
     // log comments for uninstalling the registry keys created by mail for setting
     // itself up in WinXP's Start menu