Unless you have the same db setup as default db settings in settings/site.ini, you'll get a db exception in master / beta2 currently.

This is a regression from this commit on August 16th:
http://github.com/ezsystems/ezpublish/commit/26769c017030809cdfd138d1e3af94322d5bbf01

Basically checkValidaty should be before session init code, while checkUser should be after.