Nope, not needed. There are 2 separate times you may need the disk:
1. On a fresh install of XP: If you plan on installing your OS to a RAID config, you will need to supply Windows XP with the driver files. Near the beginning of the install when it's loading all those files, you'll see a message at the bottom "Press F6 to install Third Pary SCSI/RAID drivers", hit F6. A little later, the install will ask you to supply the drivers for the Mass Storage Device, that's when you give it the floppy.
2. Installling the controller to an existing install. All you need to do is install the drivers like you would any other device, don't even need them on a floppy.