This message occurring during boot up of KNOPPIX-Live has no deleterious consequences but it is an annoyance.
It is probably an unintended hangover from the HD-installed version which allocates several partitions.
Either ignore it or include a (2nd and) 3rd (and 4th) partition in your boot device, even if it is a USB stick.
Use fdisk* to set /dev/{sda}1 as the KNOPPIX partition type c (being FAT32; or NTFS if you prefer - I've never tried this).
Set /dev/{sda}3 as type 83 (Linux) (at least 400M). Then format it as Reiserfs with mkreiserfs .
It's not obvious to me how (or even whether) the partition is used; but it is made available; and you will boot
without the annoying error message!
(*) Yes: you need to format your intended USB device - from a temporary KNOPPIX USB device is probably your most
convenient method ;o)
Professionally restored & fully recapped Commodore 64 computer | NTSC C64
$299.00
SIDKick Pico Commodore 64 and 128 (C64 / C128) - MOS SID 6581 / 8580 Replacement
$19.99
Vintage Commodore 64 Computer w/ Power Cables Joystick Manual and Original Box
$144.99
Commodore 1541-II Floppy Disk Drive 5.25 C64 with Power Supply (Works)
$125.00
TeensyROM Cartridge for Commodore 64/128: MIDI, Fastload, Emulation, and Network
$65.00
Commodore 128 Computer With Power Supply, Box, Manuals, 1571, 1541, Untested
$450.00
$160.00
Commodore Amiga 1200 Recapped NTSC 68060 FPU MMU Indivision AGA Mk3 HDMI 128MB
$1449.99
Commodore Amiga 1080 Color Monitor Read Description
$150.00
RARE Commodore KS64C Personal Computer Keyboard #’d 292/500 - Great Condition
$299.99