And it looks like the most recent version has one more table than is mentioned above.
wp_wfBadLeechers
wp_wfBlocks
wp_wfBlocksAdv
wp_wfConfig
wp_wfCrawlers
wp_wfFileMods
wp_wfHits
wp_wfHoover
wp_wfIssues
wp_wfLeechers
wp_wfLockedOut
wp_wfLocs
wp_wfLogins
wp_wfNet404s
wp_wfReverseCache
wp_wfScanners
wp_wfStatus
wp_wfThrottleLog
wp_wfVulnScanners
If your database looks like mine, ie. same tables and prefix. Run this query in phpmyadmin.
drop table wp_wfBadLeechers, wp_wfBlocks, wp_wfBlocksAdv, wp_wfConfig, wp_wfCrawlers, wp_wfFileMods, wp_wfHits, wp_wfHoover, wp_wfIssues, wp_wfLeechers, wp_wfLockedOut, wp_wfLocs, wp_wfLogins, wp_wfNet404s, wp_wfReverseCache, wp_wfScanners, wp_wfStatus, wp_wfThrottleLog, wp_wfVulnScanners