[Ted S]

Sounds like you have some duplicate thread vote records [as in there's more than one row storing votes on a thread].

There's a way to de-dup these but if you don't have much data in the system, just clear things out:

DELETE FROM helpfulpost;
DELETE FROM helpfulpost;
UPDATE user SET hagoodrank = 0, hatotalrank=0, helpfulcnt=0;

BEFORE you re-enable anything be sure to upload all of the scripts again. Parse errors don't happen due to the database, they're calculated before the script executes -- but changing settings can expose different code dependencies which can errors.