Index: /branches/release-33/lib/MT/CMS/Template.pm
===================================================================
--- /branches/release-33/lib/MT/CMS/Template.pm (revision 1737)
+++ /branches/release-33/lib/MT/CMS/Template.pm (revision 1740)
@@ -474,4 +474,8 @@
     }
 
+    # if unset, default to 30 so if they choose to enable caching,
+    # it will be preset to something sane.
+    $param->{cache_expire_interval} ||= 30;
+
     $param->{dirty} = 1
         if $app->param('dirty');