Have ensured you have your Pioneer DVR-112D connected to an Ultra DMA (80-Conductor) IDE Cable and the Master/Slave jumper is correctly set. The below Web Link provides detailed information ->
If you have confirmed that your Pioneer DVR-112D is connected to an Ultra DMA (80-Conductor) IDE Cable and the Master/Slave jumper is correctly set suggest though Device Manager removing your both your Zip Drive and Pioneer DVR-112D and rebooting and allowing your Zip Drive and Pioneer DVR-112D to be reinstalled during the rebooting procedure. If you are unaware of how to do this proceed as follows -> Navigate to Settings/Control Panel/System/Hardware/Device Manage. Once in Device Manager navigate to Disk Drives and select your Zip Drive and Right Click on your Zip Drive and select Uninstall. Then navigate to DVD/CD-ROM Dive and select your DVR-112D and Uninstall. Then turn off your computer as normally and wait a few seconds then restart your Computer. Your Zip Driver and Pioneer DVR-112D should now be correctly recognized.