SQLPLUS spawned from an NT service?

Hi, I'm trying to use a batch system on NT to spawn a job to invoke the SQLPLUS command and am running into a brick wall. I have enabled tracing because I'm getting an ORA-12545 error (host name lookup failure), and all it tells me is that it's not performing the same steps in a batch job as it is interactively. When it works from an MS-DOS window the proper execution trace looks like this:

Unable to get data from navigation file tnsnav.ora Using nnfsn2a() to build connect descriptor for (possibly remote) database. construction of local names file failed
system names file is C:\ORANT\network\admin\tnsnames.ora initial retry timeout for all name servers is 1500 csecs

The batch job's trace looks like this:

Unable to get data from navigation file tnsnav.ora Hst is already an NVstring.
Inserting CID.
Not trying to enable dead connection detection.

The messages are not very descriptive or helpful...does anyone have any idea what I need to do to make it work correctly? I have tried running the batch service as a real user rather than the local "system" account, but to no avail.

Thanks for any help anyone can provide.

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 Jim Reiss (jim_at_accelr8.com)    Accelr8 Technology, Denver, Colorado, USA