REE has a special trick...
If you're trying to install REE with RVM, and you just, for example plug in the following
rvm install ree-2011.03
It doesn't work terrifically under OS X
It also serves as a local minima of functionality, in that it will get caught with the failure condition even if you remember to add something like:
rvm install ree-2011.03 -C --with-readline-dir=/usr/local
after having done the wrong thing.
You need to do the following:
rvm cleanup all rvm install ree-2011.03 -C --with-readline-dir=/usr/local