KNOPPIX_V6.4.3DVD-2010-12-20-EN.iso - problem with command /sbin/halt

[JD <jd1008@gmail.com>]

Dear all,
I downloaded the DVD iso, and after download, I
computed it's md5 checksum. It matches the
checksum that is online:
711c259e8159477dce98e2edc3363c61

I booted this knoppix in VirtualBox.
After some finageling, trying to find a way
to change the screen resolution (and failed),
as the gnome utility would not list any available
resolutions other than 600x400 and 800x600,

I issued
halt -p

and got an I/O error message.
Tried a few more times, to no avail.

I do not know what else (command(s)) is/are broken.