Reroll Undo is back in and working as expected. Please mail us if you see any other issues.
If you have rerolled and used the undo in the last day and don't find your stats to be what you expect them to be, please let me know. I have corrected all but one of these, and have mailed that person to let them know what to do.
Please see the modified "help reroll" file. Reroll Undo will not necessarily restore hit points, stun, etc to their precise previous values, although the underlying stats are being properly restored. This is not an error or bug.