Index: openacs-4/packages/xowiki/tcl/form-field-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xowiki/tcl/form-field-procs.tcl,v
diff -u -r1.239.2.35 -r1.239.2.36
--- openacs-4/packages/xowiki/tcl/form-field-procs.tcl	22 Apr 2015 06:44:43 -0000	1.239.2.35
+++ openacs-4/packages/xowiki/tcl/form-field-procs.tcl	27 Apr 2015 14:40:37 -0000	1.239.2.36
@@ -778,7 +778,13 @@
         link_label
       }
   file instproc check=virus {value} {
-    if {[my viruscheck] && $value ne "" && [::xowiki::virus check [my set tmpfile]]} {
+    set tmpfile [my set tmpfile]
+    # In case of an upgrade script, the (uploaded) tmp file might not exist
+    if {[my viruscheck]
+        && $value ne ""
+        && [file exists $tmpfile]
+        && [::xowiki::virus check $tmpfile]
+      } {
       #util_user_message -message "uploaded file contains a virus; upload rejected"
       return 0
     }