[John]

Uninstall the product.

Run each of these queries one by one.

ALTER TABLE usergroup DROP arcadepermissions
ALTER TABLE user DROP arcadeoptions
ALTER TABLE arcade_games DROP isreverse
ALTER TABLE user DROP challengecache
DROP TABLE IF EXISTS arcade_challenges
DROP TABLE IF EXISTS arcade_categories
DROP TABLE IF EXISTS arcade_games
DROP TABLE IF EXISTS arcade_news
DROP TABLE IF EXISTS arcade_sessions
DROP TABLE IF EXISTS arcade_ratings

So far, all of the errors I've seen here were solved on my table prefix installation by the latest installation. Because I can't replicate this problem it's very difficult for me to fix it.