Here's what you'll be needing:
So let's start, simply follow the steps in the screenshots below ...
Once you OK the Content Length dialog, you should see the above screen, as if you were never blocked from sending the facebook friend request. If you get the original "this request can't be sent" screen again, just do all of the steps over again. You may have to do it a few times until it works. Eventually it will.
And that's all there is to it!Retweet buttons at the top of this post so all of your friends know where to get the good stuff!