Unable to create standby database - RMAN-11003, ORA-01620

We need to create a standby database from a production financial database. Once it reaches a certain date/time, we need to disconnect it and rename it to produce our quarterly financials. We are getting errors ORA-01620 and ORA-1507. We tried dropping the database first, but get the same errors. We've been following the same procedure every quarter for the past 4 years and have never encountered this problem before. For some reason, it keeps skipping the restore of the database and wants us to start managed recovery. Any suggestions would be appreciated.

*Script*

sqlplus -S / as sysdba <<EOF
startup nomount
alter system set cluster_database = false scope = spfile sid = '*'; alter system set job_queue_processes = 0 scope = spfile sid = '*'; alter system set standby_file_management = 'AUTO' scope = both sid = '*'; alter system set db_name = 'mrpprod' scope = spfile sid = '*'; alter system set fal_server = 'mrpprod' scope = both sid = '*'; alter system set fal_client = 'mrpfin_db1' scope = both sid = '*'; shutdown immediate
startup nomount
EOF rman log=/home/oracle/mrpfin/logs/mrpfin_dup.log_${ts} <<EOF connect target sys/"ssl#dba9mrpprod"_at_mrpprod2 CONNECT AUXILIARY /
RUN
{
  ALLOCATE AUXILIARY CHANNEL a1 TYPE DISK;   ALLOCATE AUXILIARY CHANNEL a2 TYPE DISK;   DUPLICATE TARGET DATABASE FOR STANDBY; }
EOF sqlplus -S / as sysdba <<EOF
  alter database flashback on;
  ALTER DATABASE ADD STANDBY LOGFILE THREAD 1

    group 20 SIZE 1073741824,
    group 21 SIZE 1073741824,
    group 22 SIZE 1073741824,

    group 30 SIZE 1073741824,
    group 31 SIZE 1073741824,
    group 32 SIZE 1073741824,

System altered.

System altered.

System altered.

System altered.

System altered.

ORA-01507: database not mounted

ORACLE instance shut down.
ORACLE instance started.

Total System Global Area 8388608000 bytes

Fixed Size                  2097304 bytes
Variable Size            1224740712 bytes
Database Buffers         7147094016 bytes
Redo Buffers               14675968 bytes