Currently I am responsible for a Forte 3.0.N.3 Application running on a Windows 2003 platform with the back end hitting an Oracle 8.1.6 database on an Alpha Cluster. The Alpha cluster has become unstable so we have to migrate the database to a different platform and upgrade oracle to Oracle 10g. I have installed the Oracle 8.1.7 Client on the Forte application server, as this appears to be the only client that is compatible with all versions of Oracle that we need to talk to, but now the application can't talk to oracle at all. Our DBsessions use a local tnsname entry on the application server.
SQL*Plus from oracle 8 should connect fine to the 10g backend.
Stating the obvious : can you connect to the 10g using 8 SQL*Plus client? Pointing to a listner not running on the server or an TNSnames.ora not updated on the client.
As far I remember Fort� up to 30M is linked with Oracle 7.3 binaries ... but I don't know about the 3.0.N versions. Install the 7.3 client on the 2003 machine and see if any problem arises.
If you're using a DBSession SO make sure that you still have the oracle DB resource listed at the nodemgr level on the 2003 machine.
If connecting OK via SQL*Plus make a Fort� dummy app referencing the SO DBsession that connects to the Ora 10 instance and post the logs. (Fort� uses the OCI for local connection and SQL*Net for remote)