Thanks feedback50, I bookmarked your link just in case...
I ended up doing the following which seemed to solve the issue:
1. Took a deep breath and stepped away from the computer...
2. Rebooted.
3. Ran a chkdsk /F (No problems found)
4. Turned off my Anti-virus (which I forgot to do the first time)
5. Started the installation.
This second time, I made it through the complete installation without the error. I verified the install by opening X1 and running a project. Everything seems to be working.
Now I need to install Beatscape, Dimension Pro, and the additional content.
I'll take another deep breath...