Index: openacs-4/packages/file-storage/www/folder-zip-add.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/file-storage/www/folder-zip-add.tcl,v
diff -u -r1.7.2.2 -r1.7.2.3
--- openacs-4/packages/file-storage/www/folder-zip-add.tcl	2 Jan 2016 20:13:30 -0000	1.7.2.2
+++ openacs-4/packages/file-storage/www/folder-zip-add.tcl	13 May 2016 07:07:04 -0000	1.7.2.3
@@ -7,7 +7,7 @@
 } {
     file_id:naturalnum,optional,notnull
     folder_id:naturalnum,optional,notnull
-    upload_file:trim,optional
+    upload_file:trim,optional,notnull
     return_url:optional
     upload_file.tmpfile:tmpfile,optional
     {title ""}
@@ -26,7 +26,7 @@
                 select parent_id as folder_id from cr_items where item_id=:file_id
             } -default ""]
         }
-        if {![fs_folder_p $folder_id]} {
+        if {![info exists folder_id] || ![fs_folder_p $folder_id]} {
             ad_complain "The specified parent folder is not valid."
         }
     }