I think I reproduced the problem.
If you hit that link, it'll attempt to take you to a test package I created call Gerbil. It'll ask you to login -- AS ME. You see that part in the url where it says "account"? That means the user is logged in. Stéphane cut-and-pasted the link he shared with the Squeak-dev board WHILE STILL LOGGED IN. Please don't do that or I'll unleash the CAPS LOCK OF FURY.
Logout first, please. Then find your package starting from
http://map.squeak.org and the "All Packages Sorted By Name" link.
If you cut "account" out of the url above, and try again, it'll work.
Chris