Just upgraded to Better WP Security 3.4.9 (wonderful tool, by the way!), I found that the log viewer is broken -- click on the link to view the logs, and get
HTTP Error 500 (Internal Server Error): An unexpected condition was encountered while the server was attempting to fulfill the request.
Looking at PHP error log, I see:
[05-Apr-2013 15:19:18 UTC] PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 76 bytes) in <directory>/wp-includes/wp-db.php on line 1545
Apparently I haven't checked them in a while, and now they're so big the system can't manage them...