Thumbnails are not generated, why ?
Well, I think it's the most common problem encountered by users, here is a small check list
I can't login - It does return a 404 error, page not found
The value of SCRIPT_NAME isn't filled properly by the PHP installation, you need to overide it by using the script_name directive.
As you're unable to authenticate, you'll have to edit conf/config.ini.php manually and add the following line
script_name = "index.php"
Why can I see some FIXME in this manual ?
This entry is only here because some sections of this manual are not yet fully complete and the keyword FIXME is used to locate them.