I know this is a very old thread now, but I found it whilst having the same problem.
I tried all the other things mentioned here, and as a last resort went into bios settings on mobo.
I found that the ide devices were set to "auto detect"
Even when the DMA modes were set elsewhere this was no good.
I had to manually configure the device setting for the CDRW drive in the "standard setup" menu
I can do this automatically on my mobo, by hitting f3 on the device screen to detect and save settings for each ide device. (this speeds up boot times too)
after a reboot, the drive buzzed along happily on UDMA modes. and best of all, no more coasters
Just thought id mention this incase any future web trawler happens to find it.