I made a small text change to the description a few weeks ago, and their robots that validated the code flagged something that has always passed before. So the plugin is temporarily unavailable. I'm working on getting them to fix the problem, and if that fails, I'll try to change the code to not flag the error any more. Sorry for the inconvenience. Meanwhile, this link should lead to a .rbz file you can install manually: https://github.com/clarkbremer/TFRubies/raw/master/CB_TimberFraming_2.4.6.rbz