In the default installation, Pootle does not have any user or administrator accounts defined. To enable the first site administrator, edit your users.prefs file to include a line
rights.siteadmin = True
for a user that exists. You can uncomment the example there, or add the administrator line to an existing user. Please note that leaving the example user enabled will compromise your Pootle setup, since the password is predictable. That is why it is best to add that line to a user account that already exists on your server. If you don’t yet have a registered user, you can simply create one similarly to the example. If you have a registered user who’s account is not yet activated, set the “activated” field to “1” to activate the user. Remember to restart the server for manual changes to the preference files to take effect.