I founded this error in the log :
[2012-05-13 18:17:57] (ERROR @ /connectors/workspace/packages.php) Soit le répertoire cible n'est pas un répertoire, soit il n'est pas inscriptible: /home/www/33254gdfb/web/packages/
The path is not correct, the good path would be /web/core/packages/
I migrate my site to a new server and from subdirectory to root directory.
So maybe something is wrong in the configuration.
Where is the path for package store ?