SAP - External Oracle Database Connection

I have installed Oracle Client 9.2.0.4.0 on my Linux RedHat.

Now I have SAP System and Oracle Client in the same computer.

I check the file tnsname.ora and it's ok.

Then I tryed to run tnsping and it connect to remote oracle database on Win NT.

I inserted the tnsname (alias) in the conn info field of DBCON table but I still have the same connection problem in the Native Sql EXEC SQL CONNECT TO 'identifier' statement!

Maybe the ABAP Program does not have the environment variable set for Oracle (ex. ORACLE_HOME, ORACLE_BASE),

so it can't find the tnsnames.ora file?

Can anyone help me?

Thank's in advance.

Andrea