I've had my X61t for over a year now, and I use the ultrabase on my desk at work. Problem is, after reading (any) CD, I must restart the tablet before it will recognize a different disc. In other words, if I eject a cd that it just read and install a different cd (doesn't matter media/content/brand), it will open a window and display as if there is no CD inserted. I try refresh view to no avail. After a restart, the CD is read fine. Once ejected, the drive is useless until another restart.
Windows XP SP3. I use ThinkVantage to regularly update firmware/hardware/BIOS, so it is all newer versions. The drive is HL-DT-ST DVDRAM GSA-U10N. Driver is Microsoft 5.1.2535.0