Index: trunk/ippTasks/stack.pro
===================================================================
--- trunk/ippTasks/stack.pro	(revision 14153)
+++ trunk/ippTasks/stack.pro	(revision 14681)
@@ -124,5 +124,5 @@
     # look for new images in stackSumSkyfile (pantaskState == INIT)
     book getpage stackSumSkyfile 0 -var pageName -key pantaskState INIT
-    if ($pageName == NULL) break
+    if ("$pageName" == "NULL") break
 
     book setword stackSumSkyfile $pageName pantaskState RUN