Firefox History not being cleaned

Whenever I clean my system, Firefox's Internet History is not being cleaned.

Under the applications tab, I do have "Internet History" checked under Firefox, but after a cleaning, there is no listing for "Firefox - Internet History" like there should be. When I go to Firefox, the history is still there.

I am running the latest CCleaner 2.27.1070, latest Firefox 3.5.7, and Windows XP Pro SP3.

Thanks, we'll look into this.

Also happening with Firefox 3.6.