Hi SJO!
Wow this is very old version of product and I am amazed your system is still running. I really don't remember if this version had a an Extended tools from the console screen but you can try and enter CTR ALT X then see if you can find Set Default Volume Group and Repair Filesystem and try both and see if this helps. You can try to find somewhere on the internet and look for an older version of Knoppix Linux and boot with that and try to mount those volumes. I wish I had more information for you