DVD drive problem - DMA

Okay, first off, I did try everything I have knowledge of before I resorted to ask for help.

I recently built a new computer, everything works fine except for one thing, I can't enable Ultra DMA 4 on my DVD drive. (PIO transfer mode works fine.) When I enable it by having Windows uninstall and install my secondary IDE controller, explorer crashes and reverts to PIO. I checked the jumper setting on the DVD drive, it was set to master (It's the only DVD drive in this PC, and on the second IDE controller.)

There's nothing I can do, and burning/reading DVDs is really slow and makes everything lock up if I'm doing anything else ;_; Please help, and thanks for any replies.

My epeen (specs):
ASUS K8N-DL nForce 4 motherboard
Dual AMD Opteron 242
1GB ECC RAM
DVD drive - LITEON SHW-160P6S
GeForce 7300LE (If it matters...)

by chance are you using DvDFab decryptor?

I recently had a prob. where dvdfab was changing my dvd drives from dma to PIO. I uninstalled dvdfab, then
My computer--Properties--Hadrware--device Manager--IDE ATA/ATAPI controller (then select the paralle ATA controller and instead of uninstall, just press DEL key) then reboot and let windows re-install IDE ATA/ATAPI controller.