Recently had to do a reboot and had not errors, just replayed transactions at reboot. Just to be safe, I rebooted into Knoppix 5.0x and did a reiserfsck which reported there were errors that needed to be fixed with --rebuild-tree The failed output of this is below. This has happened quite often and I have done a full reinstall several times. This is much more of an issue than ever was experienced with ext3 or even ext2.
/////////// 216224 directory entries were hashed with "r5" hash. "r5" hash is selected Flushing..finished Read blocks (but not data blocks) 1049994 Leaves among those 44826 - corrected leaves 1 - leaves all contents of which could not be saved and deleted 3 Objectids found 215800 uname -a <= a custom kernel from kernel.org download and build Linux deskstation 2.6.17.1hanaden #1 SMP PREEMPT Wed Jun 28 18:34:21 CDT 2006 i686 GNU/Linux Has been occurring with lower kernel numbers and those that come with both Debian and Ubuntu