Eric,
As you said, if your getting that error when trying to install the Firmware updates, there is a missing piece on your system. This is definately your problem for everything. You must install the file that I am going to email you to the exact location that it states in the email, and it should ask you if you want to overwrite and say yes. If this still doesn't fix the problem with you being able to update the Firmware, I would try calling Plextor and see if they can tell you what is wrong. There website is
www.plextor.com.