We've already traced a workaround for this kind of error.

Failed to initialize storage module: user (path: /tmp) in /srv/www/htdocs/elib/polerio/lib/Session.php on line 214

To solve this problem modify this file

# vi polerio/lib/Session.php

Then look for this line

ini_set('session.save_handler', 'user');

Replace it with: on line 64

ini_set('session.save_handler', 'files');

Give us some feedback if this doesn't still work.
This modification applies only to php-5.0.x users.