Sounds like the filesystem may be in need of an fsck. Boot into the
rescue environment by inserting CD1 of the install media and typing
fsck didnt find anything to complain about. Filesystem seems to be ok.
Found the solution, when I tried to reinstall FC3 on the same partition:
There were two GRUB entries with the same LABEL for root
Changing that, resolved the issue.
Thanks for your help.
/dev/loop
