Are you using version 2.0.1 of the hack?
Could you dump out the moderator info from the database?
SELECT U_Username,U_Status,U_Groups
FROM w3t_Users
WHERE U_Status='Moderator'
SELECT G_Name,G_Id
FROM w3t_Groups
WHERE G_Name='Moderators'
SELECT Mod_Board,Mod_Username
FROM w3t_Moderators
SELECT Bo_Keyword,Bo_Moderators
FROM w3t_Boards
In w3t_Boards.BoModerators, are all the moderator names both preceded and followed by a comma? It should look like: ",mod1,mod2,mod3,". If the comma at the beginning or end of the string is missing, that would explain the problem, because the hack assumes they're present.
If the commas are present, there may be an inconsistency among the above tables.