I experimented with this module - adding instances or rolls for multiple weeks works well. However, problems arise in it's use. Basically the instructor clicks on the attendance activity in order to record attendance for that class, and then clicks the 'take attendance' link. This enables one to update attendance for individual students. However, clicking the 'save changes' not only does not save any change you made but all the attendance information gets reset to a default value. Thus with 'take attendance' not functional there is no way to actually change attendance and no way to accumulate the attendance grade. This is illustrated more transparently in the movie linked by the URL.
I can replicate this with Firefox & I.E on Windows as well as Safari & Firefox on mac. We're using Moodle 1.3 and the latest ZIP (July 20th mod) of Attendance.