forgive the silly question, but have you verified that these offsets are not beyond the end of the partition?
you can test reading partitions easily with
dd -if /dev/sdC0/isect -of /dev/null -bs 64k
it wouldn't be too hard to write a scrubber that reads and
then rewrites the disk. it should try the rewrite twice
in case the bad block allocation policy is to return
a write error and then allocate a spare block.
(this is the case with many drives.)
- erik
