Netgear FVS318 site blocking no longer works

I use my FVS318 to block pages that are notorious for ad-ware, installing malware, and logging activity. It used to block these like a champ but is now letting through pages that were once blocked.

Here's what I have configured on the 'Blocked Sites' page:

- "Turn Keyword Blocking On" is CHECKED

- "Block Sites Containing These Keywords Or Domain Names" has lots of sites blocked (actually as many as it will hold so I can't add any more)

- "Allow Trusted IP Address To Visit Blocked Sites" is NOT checked

Any idea why the blocking no longer works even though the list of blocked sites is still intact?

Thanks.