The module doesn't work when the master is behind Basic Authentication, because it fails on the drupal_http_request() in bakery_request_account().

drupal_http_request() supports Basic Authentication according in Drupal 6 and Drupal 7.

In Drupal 7, this seems easy because one can just set the 'proxy_username' and 'proxy_password' variables. If set, they are picked up drupal_http_request() by default. For D6 we might have to add two fields on the Bakery settings form for this?