Can be a couple of things?
If you're unsure of what the bios is or what to do in it, don't bother. Some bios have a U-DMA option that on some m/b's is set to Disable by default. You can also change the LiteOn settings to maybe Mode-4 if it's set to AUTO.
I'm assuming you're runing WinXP, it's been so long for me I've forgotten (thankfully) with the Win9x/Me configuration.
Start/Control Panel/System/Hardware/Device Manager/IDE ATA/ATAPI Controllers
and depending on where the LiteOn is installed, select either Primary or Secondary IDE Channel, right-click and select Uninstall, then ReBoot.
If all goes well when WinXP reboots, the LiteOn will now be Ultra DMA Mode 2.
Hope this helps