Index: trunk/ippScripts/scripts/detrend_stack.pl
===================================================================
--- trunk/ippScripts/scripts/detrend_stack.pl	(revision 16561)
+++ trunk/ippScripts/scripts/detrend_stack.pl	(revision 16563)
@@ -191,5 +191,5 @@
 
     carp($msg);
-    if ($det_id and $iter and $class_id and not $no_update) {
+    if (defined $det_id and defined $iter and defined $class_id and not $no_update) {
 	my $command = "$dettool -addstacked";
 	$command .= " -det_id $det_id";