I am friends with someone on facebook and I just tried to post something on his wall and I got a message that said "message cannot be posted on this wall."
Someone else posted a message to him 3 hours earlier.
I'm pretty sure if you are blocked, there wouldn't be the message box there at all to even post - but I could be totally wrong. My guess is that it was an error but I'm not entirely sure.
I've only ever seen it where you can either post to someone's wall or you can't - in fact I think the option is to check a box - I don't think you can customize who can post to your wall. You can customize who can see posts to your wall. Again, I could be totally wrong though.
Earlier today I went to comment on April's bejeweled blitz post and it wanted me to do a security code to be able to post the comment. Yet no code would come up. I finally just went back to my main news feed and posted to the post again and it went right through.
