This happens because XP does not have the Buslogic SCSI drivers built in. What you need to do is to attach the virtual driver floppy (vmscsi.flp) which can either be found in the "Resources" sub-directory of the VMware Workstation installation or at http://download3.vmware.com/software/vmscsi-1.2.0.4.flp and add the driver by pressing F6 while XP boots (see e.g. http://kb.vmware.com/kb/1000863).
André