Why I can't access to dblog? Why I can't access "Recent log messages" (via /admin/reports/dblog)?

It's not listed in the Admin Menu. And when I try to get there directly (via /admin/reports/dblog), I only see the "Reports", as shown via /admin/reports.

I've installed Drupal 7.15 with the OpenPublish Profile.

What could be the solution to this problem?
As suggested, Check whether "Database logging" module is enabled in your modules list.