Hmmm, I think the questions need to go further back in the whole process ... I'm not sure whether, or not, you're implying a problem with the windows partition itself...

1) Are you able to mount hda1 from the Live CD | DVD ?
1A) (and if not, was the media integrity validated OK on booting with the cheatcode knoppix testcd ?)

If 1) is OK then we can infer that the problem lies with the HD-installed Knoppix

Otherwise, are you trying to mount either:
2) a known-working Windows partition for working data transfer TO of the Linux system ? (NB if you try FROM Linux it's at possible risk to your NTFS filesystem - numerous postings on the forum refer)
or
3) a Windows partition with a problem to be rescued from Linux ?

If the answer is 2) or 3) the problem would seem to be related to the NTFS partition itself. I'm afraid I can't help much there, not having used NTFS since the days of Windows NT4, and I would not have it on a machine where I also use Linux
Oh,
4) You tried chkdsk ; if you run whichever of gparted and|or qtparted is on your Knoppix, or a GParted Live CD, does that give any more information?