cdrom mounted, but symlinks ( stable -> .) are no symlinks but an empty file

Hi

When installing Ubuntu from cdrom (expert or normal Boot-Option),
the cdrom-boots fine and Installer-Menu appears.
Language, Location, Keyboard layout and even "Detect and mount cdrom" too.

But the next menu point "Load installer components from cd-rom" an error message
is shown:
"There was a problem reading data from the CDROM. ..."

On the 4th console (ALT-F4) I can read:
... anna[3853]: grep:
... anna[3853]: /cdrom/dists/stable/Release
... anna[3853]: : Not a directory

In the shell (ALT-F2):
  * ls -l /cdrom/dists
    shows, that "local, stable, testing an unstable" are just empty files
instead of symlinks.

When I boot the installed OS (Knoppix 3.1, 2.4.? Kernel)
The CD-ROM is mounted correctly an the symlinks mentioned above are real
symlinks and not just ordinary files.
But in Knoppix hdc (my cdrom-drive) is mounted with the Kernelmodule Options
(hdc=scsi (written in /etc/lilo.conf) )

I also tried to boot Ubuntu with that option (expert hdc=scsi) but there was no
difference.
(I' m not sure if that boot-option is still supportet in kernel 2.6; any idea
what i should use instead?)

I assume that it could be a problem with the "ide_cd" Kernel modules, because
Knoppix 3.1 uses scsi emulation and works fine. I could also install older
Mandrake Linuxes without problems (8.?), but "newer" ones (9.1) failed too.

Here are parts of the output while trying to install Ubuntu:
  hcd: ATAPI 24x CD-ROM drive, Revision: 3.20
  ide-cd: cmd 0x28 timed out
  hdc: DMA interrupt recovery
  hdc: lost interupt
  hdc: status error: status=0x58 { DriveReady SeekComplete DataRequest }
  hdc: status error: error=0x00
  hdc: drive not ready for command
  ide-cd: cmd 0x28 timed out
  hdc: DMA interrupt recovery
  hdc: lost interrupt
  hdc: status timeout: status=0xd0 { Busy }
  hdc: status timeout: error=0x04Aborted Command
  hdc: DMA disabled
  hdc: drive not ready for command
  hdc: ATAPI reset complete
  ISO 9660 Extensions: Microsoft Joliet Level 3
  cdrom-detect: Detected CD 'Ubuntu 4.10 "Warty Warthog" - Preview i386 Binary
(20041020)'

Any idea what i have to do to install Ubuntu?

Please let me know if you need any more informations.

Thanks for the help in advance
Best Regards
Philipp

Software : Ubuntu Linux 4.10 "Warty Warthog" (20041020) (from "Linuxuser
magazin" 12.2004)
Kernel : 2.6.8.1-3-386
Notebook : Dell Inspirion 3500 (P II processor/333Mhz,128Mb RAM)
CD-ROM Drive: Thoshiba XM 180 2B