Test connection failed because of an error in initializing provider. ORA-12154: TNS:could not resolve the connect identifier specified

I am not able to connect to oracle from SSIS project. I have installed SQL Server 2005 on Windows server 2008 64 bit. However, I can do it from C:\PROGRA~2\Microsoft SQL Server\90\DTS\Binn\dtswizard.exe I am getting below error on connection:

Test connection failed because of an error in initializing provider. ORA-06413: Connection not open. Test connection failed because of an error in initializing provider. ORA-12154: TNS:could not resolve the connect identifier specified