rvm install: ruby installation error

Uninstall and reinstall rvm with

bash -s stable < <(curl -s https://raw.github.com/wayneeseguin/rvm/master/binscripts/rvm-installer)

For posterity, I'll add that the part of the error that says

Installing Ruby from source to: /usr/share/...

is what got me thinking about a broken installation of rvm which, as I said, is normally entirely contained in the ~/.rvm directory.

I solved my problem simply doing:

rvm get head rvm reload and rvm install 1.9.3