NT4.0 client SQL*Net problem

I'm having a very curious problem with SQL*Net 2.3 when running from NT4.0 (Intel x86 client).

It all started when we upgraded our client and server (HPUX) from Oracle 7.1.6 to 7.3.2. When our ODBC application runs on the client, we get the following error:

ORA-12154: TNS:could not resolve service name.

I know that this error usually means that I have botched the SQL*Net setup somehow. My next move was to use the ODBC test applications (both Microsoft and Oracle have them!) to debug the setup. To my surprise, both connected to the server with no problems. SQL*Plus also works from the NT client with no problem.

So far, I've already tried the following steps to try to solve the problem:

1. I've turned on trace in the SQLNET.ORA file (trace_level_client=16). It generates a marvelous trace file for both of the ODBC test programs, and absolutely nothing when I run from ODBC.
2. I've checked that SQLNET.ORA and TNSNAMES.ORA are in the right place and have the right syntax. I generated them with SQL*Net Easy Configuration, but I get the same results whether I use the generated version, or if I edit a text version with NOTEPAD.
3. I've tried running TNSPING <server_name> to see if that would give me any information. I see a dump which indicates that it is finding the correct TNSNAMES.ORA file, but it tells me that the listener is not running (TNS-12541). I know that the listener is running, because I can still access it via ODBC test or SQL*Plus.
4. I've verified that ORACLE_HOME and TNS_ADMIN are defined both as Windows system variables and as NT Registry entries. I've tested each of the combinations (system variables alone, Registry entries alone, and both together).
5. I've gone as far as to remove all traces of the Oracle drivers (both OCI and ODBC, all versions) and re-install ONLY 7.3.2 (and ODBC 2.5) from scratch.

I've looked over all of the documentation on the Oracle Tech Net site, and I've looked over 2 years worth of comp.database*.oracle.* entries to try to find an answer, but I can't find anything I haven't already tried. I would really appreciate any insite that anyone could give into this problem.

Thanks,

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Steve Culy
Visual Numerics, Inc.
sculy_at_boulder.vni.com   voice:(303)245-5328