Error can occur for different reasons.
ORACLE_HOME in /etc/oratab(and defaults.yaml) is different from that of env.
1.cat /etc/oratab
st5511:/u01/app/oracle/product/10.2.0/db_1:N
2.echo $ORACLE_HOME
/u01/app/oracle/product/10.2.0/db_1/
So the ORACLE Instance IPC key changed.
If the error ORA-1034 is associated with ORA-1031, it's an error when running ora_setup with DBA user missing the SYSDBA privilege.
Workaround 1:
a.remove the "/"
old: export ORACLE_HOME=/u01/app/oracle/product/10.2.0/db_1/
new: export ORACLE_HOME=/u01/app/oracle/product/10.2.0/db_1
b.bounce the oracle instance.
