Spam protector plugin not working?

[Beepmode]

For some reason the Spam Protector plugin on my blog isn't preventing a single spam message. On the 'Configure Plugins' page it shows it's an active 'event plugin' but somehow it's not working. This morning I set 'Emergency comment shutdown' to 'Yes', but even that hasn't stopped the flood.

I suspect I'm missing something obvious. The comment area on blog entries shows a captcha image, so I guess the way I configured the plugin is wrong. I tried changing the settings, read the documentation, searched the w3 but I seem to be the only person on the planet with this issue.

I'm using Spam Protector 1.77 with Serendipity 1.5.5 and PHP 5.2.17. The blog is at www.blogs.stopjunkmail.org.uk/diary.

[Timbalu]

Spam protector has been updated due to some better spam settings and the emergency shutdown has been improved. You could try and update to Serendipity 1.6.2, which has the current version 1.79 on Board. Then play around with the settings or even add filter words.
If that all does not help, install additional the Spamblock bayes Plugin and get it learn your spam flood.

Good luck.

[Beepmode]

Thanks for the suggestion - I'll try upgrading later this week (dreading it) and will report back.