lucy24 - 8:43 pm on Feb 20, 2012 (gmt 0)
What does your host's redirect do? If "yoursite.com" is, uhm, your site, then it seems as if it would redirect to the same file the user requested in the first place. This is fine if it's a robot, because they probably won't follow the redirect. Easy way to get rid of them. But if it's a genuinely new human, they'll never get there. Their own browser-- not your server-- will look at what's happeneing and slam the door.
Use www.example.com to keep examples from turning into clickable links. Oh, and the [NC] flag isn't needed, since no exact text is specified in the rule. But the Conditions are the important part, and you've got those.