Self-followup--I realized that part of the issue is that Knoppix appears to like hard drives read-write by default, and NTFS write support is kind of limited (capture, as I understand it, uses the HDD to find the drivers).

I tried mounting read-only, which worked. However, I can't see any files. Less promising, but possibly recoverable with the right utility? Ideas welcome...

root@1[dev]# mount -r /dev/hda1
root@1[dev]# cd /media/hda1
root@1[hda1]# ls
ls: reading directory .: Input/output error
root@1[hda1]#