After attaching a ReiserFS disk to a devel box, after sudo fsck /dev/sde2, I've got this error:
fsck: Error 2 while executing fsck.reiserfs for /dev/sde2
This is not an issue with permissions or so, it's simply the error that fsck can't find the reiser related tools. Do this:
sudo apt-get install reiserfsprogs
and your're all good.