Index: trunk/ppBackground/src/ppBackgroundStackData.c
===================================================================
--- trunk/ppBackground/src/ppBackgroundStackData.c	(revision 36580)
+++ trunk/ppBackground/src/ppBackgroundStackData.c	(revision 36582)
@@ -21,4 +21,6 @@
   psFree(data->modelMap);
 
+
+  psFree(data->stack_data);
   psFree(data->stacks);
   psFree(data->outRoot);
@@ -45,5 +47,6 @@
     data->dec_min  = 1e9;
     data->dec_max  = -1e9;
-    
+
+    data->stack_data = psArrayAlloc(0);
     data->stacks = psArrayAlloc(0);
     data->outRoot = NULL;