Oracle Database Discussions

I am getting the following error message when connecting from a client pc (PC-A) (10.1.0.4) Suse to a 10.1.0.2 database running on Unix. TNS-12547: TNS:lost contact

I have another client pc (PC-B) (also Suse) which I can use to successfully connect to the database. The sqlnet.ora and tnsnames.ora files are exactly the same on both client pc's. The only difference is that PC-A is connecting through a firewall and PC-B is not, but we opened the firewall for testing purposes and it did not work. We even reinstalled the Oracle client but it did not work.

Any ideas on this?

Fatal NI connect error 12547, connecting to:
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=OracleServer)(PORT=1521))(CONNECT_DAT
A=(SERVICE_NAME=orcl)(CID=(PROGRAM=sqlplus)(HOST=PCA)(USER=root))))

VERSION INFORMATION:
TNS for Linux: Version 10.1.0.4.0 - Production
TCP/IP NT Protocol Adapter for Linux: Version 10.1.0.4.0 - Production
Time: 15-FEB-2006 20:41:25
Tracing not turned on.
Tns error struct:
ns main err code: 12547
TNS-12547: Message 12547 not found; No message file for product=network, fac
ility=TNS
ns secondary err code: 12560
nt main err code: 517
TNS-00517: Message 517 not found; No message file for product=network, facil
ity=TNS
nt secondary err code: 104
nt OS err code: 0