Index: openacs-4/packages/acs-tcl/tcl/stack-trace-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/stack-trace-procs.tcl,v
diff -u -N -r1.3.12.2 -r1.3.12.3
--- openacs-4/packages/acs-tcl/tcl/stack-trace-procs.tcl	10 Sep 2015 08:22:00 -0000	1.3.12.2
+++ openacs-4/packages/acs-tcl/tcl/stack-trace-procs.tcl	27 Nov 2016 12:19:35 -0000	1.3.12.3
@@ -26,7 +26,7 @@
         } else { 
             set callStack {}
         }
-        for {set i [info level]} {$i > 0} {set i [expr {$i - 1}]} {
+        for {set i [info level]} {$i > 0} {incr i -1} {
             set call [info level $i]
             if {[string length $call] > 160} {
                 set call "[string range $call 0 150]..."            }