The password file must be under $ORACLE_HOME/dbs
The file name MUST be "orapw" and you must use the SID for the database in which the password file is being created. Do not add an extension to the file name.
Do the following:
1. Shutdown immediate the database.
2. cd $ORACLE_HOME/dbs.
3. orapwd file=orapw password= entries=
4. In the init.ora file, add REMOTE_LOGIN_PASSWORDFILE=exclusive