Why is ratchet not installed?

Question

Composer

I installed composer ( socketo.me/docs/install)
I create composer.json according to the guide
I write in the console

php /var/www/web/data/www/**** domain *****/composer.phar install

gives an error message:

Loading composer repositories with package information
Installing dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - cboden/ratchet v0.3.2 requires php >=5.3.9 -> no matching package found.
    - cboden/ratchet v0.3.1 requires php >=5.3.9 -> no matching package found.
    - cboden/ratchet v0.3.0 requires php >=5.3.9 -> no matching package found.
    - Installation request for cboden/ratchet 0.3.* -> satisfiable by cboden/ratchet[v0.3.0, v0.3.1, v0.3.2].

Potential causes:
 - A typo in the package name
 - The package is not available in a stable-enough version according to your minimum-stability setting
   see <https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion> for more details.

Read <http://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.

PHP Version 5.4.15 is worth it!