the NLS_DATE_FORMAT on both db's in DD-MON-RR (!) but the view defines its date columns with to_date(xxxx,'DD-MON-YYYY HH:24:MI') in the select query, so thats whats causing the problem. The snapshot gets dropped and re-created weekly so I guess one solution is to put an alter session set nls_date_format='DD-MON-YYYY HH:24:MI' in the top of the script that drops/re-creates it. Any other suggestions would be welcome!