Using the standard Delphi dbexpress dbexpora.dll + oci.dll (10g) (the oracle instantclient is installed).
When directly on the Oracle Database box we can run dbexpress apps just fine. The local dbxconnections.ini alias used in that case simply specifies our DB service name ORCL as the "database" parameter.
We are trying to connect to this same database from client machines and receiving a series of errors.
Naturally, we are trying all manner of strings in the database parameter. Using a string like, MOHAWK2:1521:ORCL we are at the point where we can at least get a listener error:
Failure to Connect: ORA-12514 TNS:listener does not currently know of service requested in connect descripter.
I imagine there are some tools to test the naming availability...