What version are you running?
2.0+
What's the URL of the page containing the problem?
/admin/settings/*

What is the problem?
The forms in reviewboard.admin.forms use ugettext (as _(...)) for the form fields, which means they're localized at application initialization time rather than at page render time. They should be using ugettext_lazy as _(...).
The code inside of functions that use ugettext should continue to do so, since those happen at render time.
So:

We should update the _ alias to be for ugettext_lazy instead of ugettext, for anything used as members of the forms.
We should import ugettext and call that specifically for anything happening within a function.