If RSS2Twitter.com does not work for you, try http://twitterfeed.com. If that doesn't work for you either, try burning your Yahoo! Pipes RSS feed with http://feedburner.com. Then take that feed and put it in to Twitterfeed.com to send it to your Twitter bot account.
This method is an adaptation of Keith Hopper's method for creating @NPRbackstory. His website is http://keithhopper.com