As the SiteScope doc says, you should install the oracle thin client to monitor oracle with sitescope. The driver files are available on the oracle website, and the classes14.jar file attached to this page should work also. This jar file should first be added to a zip file names classes14.zip. Once the jar file is in a zip file it can be added here:
[SiteScope Home\WEB_INF\lib Once it's there, restart SiteScope. The Oracle driver name for the monitors will be "oracle.jdbc.driver.OracleDriver".