I have a volume with "Volume Retention = 5184000" (60 days) Webmin displays this as 5184000 DAYS. Changing the setting to Seconds, webmin inserts a quoted string in the configuration, which results in an error:
ERROR in parse_conf.c:704 Config error: expected a time period, got: 5184000 seconds
: line 241, col 38 of file /etc/bacula/bacula-dir.conf
Volume Retention = "5184000 seconds"
Bacula 2.4.4-10 on CentOS 5.8