ORA-12701: CREATE DATABASE character set is not known

ORA-12701: CREATE DATABASE character set is not known
While Starting the database, I had faced the error - ORA-1092 signalled during: ALTER DATABASE OPEN...
then check in the Alert.log it shows the messages like below:
ORA-12701: CREATE DATABASE character set is not known
Thu Jul 9 19:10:14 2009
Error 12701 happened during db open, shutting down database
USER: terminating instance due to error 12701
Instance terminated by USER, pid = 28018
ORA-1092 signalled during: ALTER DATABASE OPEN...

Solution:
I had checked $ORA_NLS10 path. Instead of “$ORACLE_HOME/nls/data/9idata”,
it points to the Wrong one like below:

echo $ORA_NLS10
ORA_NLS10=/aplvol01/CRP/oracle/CRP/db/tech_st/10.2.0/ocommon/nls/admin/data

Change the env file to the correct path and start the database.