(MU_ERR_EXISTS): New error code

 # Error messages for GNU Mailutils
-# Copyright (C) 2005, 2006 Free Software Foundation, Inc.
+# Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
 #
 # This library is free software; you can redistribute it and/or
 # modify it under the terms of the GNU Lesser General Public
@@ -68,6 +68,7 @@ MU_ERR_PROCESS_UNKNOWN_FAILURE _("Unknown failure while executing subprocess")
 MU_ERR_CONN_CLOSED          _("Connection closed by remote host")
 MU_ERR_PARSE                _("Parse error")
 MU_ERR_NOENT                _("Requested item not found")
+MU_ERR_EXISTS               _("Item already exists")
 MU_ERR_BUFSPACE             _("Not enough buffer space")
 
 MU_ERR_SQL                  _("SQL error")