i have the same problem, but i saw that during the cb login module installation come up on the screen for 2 seconf this:

Warning: constant() [function.constant]: Couldn't find constant JPATH_ in /web/htdocs/www.name.it/home/name/libraries/joomla/installer/adapters/module.php on line 74

Warning: constant() [function.constant]: Couldn't find constant JPATH_ in /web/htdocs/www.name.it/home/name/libraries/joomla/installer/adapters/module.php on line 76

i think the problem is aroud here...
somebody can help us??