Oracle Database Discussions

Hello there,

I've a problem with a client installation if I try to connect to the database. I've the following configuration:

1. Database: Running on a Ubuntu Jeos VM, Oracle 11g (Release 11.1.0.6.0 64 bit)
2. Client: Running on a CentOS 5.2 VM, Oracle Client 10g Linux 32bit

I've configured the tnsnames.ora and stored it in the $ORACLE_HOME/network/admin directory. The content of the tnsnames.ora file is the following:
ORCL64=(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.12.128)(PORT=1521)))(CONNECT_DATA=(SID=orcl)))

If I try to connect to the database as the oracle user with the following command sqlplus SYS@ORCL64 AS SYSDBA, I'll get the ORA-12154 TNS:could not resolve the connect identifier specified error message. If I try the same as the root user it works fine and I can establish the connection. The same result I've got if I try the command tnsping ORCL64. As the root user the tnsnames adapter can resolve the alias, as the oracle user this is'nt possible and I'll get the error message: TNS-03505: Failed to resolve name. In both he uses the paramter file /u01/app/oracle/network/admin/sqlnet.ora. The content of the sqlnet.ora file is the following:
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT).

Have you any suggestions how can I resolve this problem to get a connection with the oracle user.
Thank you in advance
Sven