I don't get it.
You have 787 members shown but 790 rows in the table?
OK one of them is user#1 the placeholder for anonymous users. So then you had 2 that were not yet verified, right?
What is the count if you do this:
SELECT COUNT(*)
FROM w3t_Users
WHERE U_Approved = 'yes'
Is that 787 or 788?
Or does that come back the same as the main index page?
I don't know why the ubbthreads script would be counting wrong