Index: openacs-4/packages/xowf/tcl/xowf-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowf/tcl/xowf-procs.tcl,v
diff -u -r1.3.2.12 -r1.3.2.13
--- openacs-4/packages/xowf/tcl/xowf-procs.tcl	7 Mar 2017 09:28:58 -0000	1.3.2.12
+++ openacs-4/packages/xowf/tcl/xowf-procs.tcl	27 Mar 2017 10:37:42 -0000	1.3.2.13
@@ -490,7 +490,7 @@
     if {[catch {exec $dot -Tpng $fn -o $path/$ofn} errorMsg]} {
       my msg "Error during execution of $dot: $errorMsg"
     }
-    file delete $fn
+    file delete -- $fn
     return "<img style='$style' src='[$package_id package_url]/$ofn'>\n"
   }