Is this how it starts?

ReiserFS: hda5: warning: vs-8115: get_num_ver: not directory item
ReiserFS: hda5: warning: vs-8115: get_num_ver: not directory item
ReiserFS: hda5: warning: vs-8115: get_num_ver: not directory item
ReiserFS: hda5: warning: vs-8115: get_num_ver: not directory item
ReiserFS: hda5: warning: vs-8115: get_num_ver: not directory item
ReiserFS: hda5: warning: vs-8115: get_num_ver: not directory item

That's what the final bit of the output of dmesg on rock looks like, currently. Need to backup, mkfs, restore that one. Only I'm not sure I have enough free space elsewhere to do the first bit. Hrmpf. May need a new hard disk.