you need to set the Path as well as classpath when using the OCI drivers:
JDBC OCI Driver:
If you are installing the JDBC OCI driver, you must also set the following value for the library path environment variable
On Solaris, set LD_LIBRARY_PATH as follows:
[Oracle Home]/lib
This directory contains the libocijdbc9.so shared object library.
On Windows NT, set PATH as follows:
[Oracle Home]\lib
This directory contains the ocijdbc8.dll dynamic link library.
you can read more in the
Oracle9i JDBC Developer's Guide and Reference. The above exerpt was taken from chapter 2 - getting started.
Jamie