HP Performance Center - Support Tip : Prerequistes for setting up Oracle monitors
To add Oracle monitors in Performance Center you must install the Oracle Client in Performance Center Server machine. Also, the client must be 32-bits installer.
Make sure that there is connection between the Database server and Performance Center server using SQL plus tool (it is on your Oracle Client installation folder). This is required in order to add Oracle monitors.
For additional details you can check the following article here for your reference.