Hi,

Please upload the entire tnsnames.ora of the client machine connecting to the RAC DB and the listener.log from each of the nodes.

Suspect there is a problem in configuring the tnsnames.ora for the client, there has to have a common service name to connect to the instances...

Also, please provide output if SQL client is able to connect to the RAC DB.

On the CLient:

SQL> conn system/@

Regards,
Paresh