Can't connect from Linux to NT

I am having troubles connecting from a Linux client to an NT server. My setup is as follows:

Server:
WinNT4 SP6
Oracle 8i 8.1.5 enterprise
Linux client:
Red Hat 6.2
glibc 2.1.3-15
Oracle 8i 8.1.6 client

Windows client:
Windows 2000 Pro
Oracle 8i 8.1.6 client

I can TNSPing the server from both clients, and I can connect with sqlplus fine from the Windows client, so long as I am logged into the domain. I cannot connect with sqlplus from the Linux client though. Here is my attempt logged on as me:

matt_at_dem01 bin$ ./sqlplus matt_at_gedb.secsys.comSQL*Plus: Release 8.1.6.0.0 - Production on Mon Mar 5 08:20:06 2001(c) Copyright 1999 Oracle Corporation. All rights reserved.Enter password: ERROR:Error while trying to retrieve text for error ORA-06401Enter user-name: mattEnter password: ERROR:Error while trying to retrieve text for error ORA-12545Enter user-name: systemEnter password: ERROR:Error while trying to retrieve text for error ORA-12545SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus
And then, logged on as root:

root_at_dem01 bin# ./sqlplus system_at_gedb.secsys.comSQL*Plus: Release 8.1.6.0.0 - Production on Mon Mar 5 08:27:32 2001(c) Copyright 1999 Oracle Corporation. All rights reserved.Enter password: ERROR:Error while trying to retrieve text for error ORA-06401Enter user-name: systemEnter password: ERROR:Error while trying to retrieve text for error ORA-12546Enter user-name: mattEnter password: ERROR:Error while trying to retrieve text for error ORA-12546SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus
(ORA-12545 = TNS:name lookup failure, ORA-06401 = NETCMN: invalid driver designator)

Does this have something to do with user accounts on the NT server? Any help/suggestions much appreciated.

Thanks,
Matt Received on Sun Mar 04 2001 - 20:27:46 CST