Okay, well, I now have a kubuntu system installed, and I'm getting the same exact error message. Could it have something to do with the fact that I'm working from a system that is also installed on an external hard drive?
Is there any reason to hope that VL6, unlike VL5, will install on the external hard drive from a CD in the usual way? Maybe I'll give that a shot. If not, I've got an old computer that might just be the thing I need.