Just tried to post a quick reply to a post and got the above message. I have got a similar message in the past (usually if I post offsite links) where I had to enter the text in the box (capcha type thing), but this time its not even offering me that option! Its just flatly refusing to accept my post! Any ideas?
 I just got around the spam filter by changing the links to text (ie not links) but its not ideal (see the post here).