Access denied on node/nid/spaces/features

Hi,

Don't know what is wrong but I tried multiple times, with a fresh Drupal + Spaces + Context + Features installation, and I've an access denied page when I try to edit the group node feature's.
The default homepage is ok, and I can access to it, but I can't edit features for a specific node. In fact in spaces_admin_access(), spaces_get_space() return NULL (line 1328 of spaces.module).

What did I made wrong ?

Thanks.