STPI

SCSI Pass Through Interface
INFO: SCSI Pass Through Functionality and Limitations
On Windows NT and Windows 2000, the interface used in an application to send SCSI commands to a SCSI device is called SCSI Pass Through (SPT). A Win32 program uses DeviceIoControl with the IoControlCode of IOCTL_SCSI_PASS_THROUGH or IOCTL_SCSI_PASS_THROUGH_DIRECT.
Source
You need administrative privileges to use SPTI
SPTI is available to Administrators only. Microsoft designed it like this, don't blame me!
Here is a quick workaround for those people wanting to stick with SPTI

• Log in as an Administrator
• Click 'Start' -> 'Run'
• Type 'secpol.msc' and hit OK
• Expand 'Local Policies'
• Click 'Security Options'
• Change 'Devices: Restrict CD-ROM access to locally logged-on user only' from 'Disabled' to 'Enabled'
• Close the 'Local Security Settings' window
• Log on as your restricted user and try again.

Note: Only tested on XP and Server 2003. Wording may differ on other operating systems.
If you're not bothered about sticking with SPTI, Install ASPI or an application that installs ElbyCDIO on your machine - i.e. CloneDVD*. Then go into the settings and on the I/O tab, select the appropriate 'Interface'.
*CloneDVD can be downloaded from www.elby.ch

DVD Burner and SPTI issues in XP Home Edition SP3