Is the oracle client software installed?

You need to run the Oracle installer for your database version.
Then select client install.

The minimum you need is Net8 (for oracle 8 and up!)
If you have installed it already you may need to restart or check your
PATH=
Statement in the autoexec.bat or confisg.sys (if using windows 95)

Becuase the should be your oracle bin folder in your program path.
I once had a problem where the path had a space in it like:
PATH=c:\temp;c:\windows; c:\orant\

Have you seen the Oracle Objects for OLE they are brilliant.

Hope that helps...