firebird.msg not found

D:\firebird\bin>isql -u sysdba -p masterkey D:\firebird\OpUtilsDB.fdb
can't format message 17:0 -- message file D:\firebird\firebird.msg not found
unavailable database
can't format message 17:3 -- message file D:\firebird\firebird.msg not found
SQL> exit;

To solve this problem,

1. Stop if you have any firebird instances running
2. Change the value of the var 'CreateInternalWindow' as 1 in firebird/firebird.conf
3. Start firebird (run fbserver -a from firebird/bin)
4. Then run the isql command