Did you install oracle client on the machine? Can you do "tnsping <SID>"? Can you connect to DB using sqlplus ?
Try using tnsname for server name.
Connecting to Microsoft Data Sources Through ODBC Connection This shows how to connect using ODBC connection. I think this would be more appropriate.
Are you using Microsoft ODBC driver for Oracle or Oracle ODBC driver for Oracle? What is the exact version of Oracle that you using (both client and server)?
Most common/known issue on Windows 64bit version which causes this issue and their solutions are listed below:
If your application name, username or password, has some special characters like parenthesis or quote etc, then ORA-06413 error may be thrown. Try after changing it some normal characters.
Also try installing Excel in different directory other than default directory ("c:\program files (x86)\") since it contains parenthesis.
Thanks & Regards,