by Mark Pearson.
Well done Erik -- take a Moodle Administrator star for sorting out the problem and reporting it's solution. There is however one more step. It looks like you've discovered a bug in the Attendance module for 2.5.1. The next step is to create an account for yourself in the Moodle bug tracker and click on 'Report a bug in Moodle'. Then fill in the form as best you can giving the precise steps to reproduce the problem (I take it that it is reproducible). This'll get you an extra M.A star -- you're probably the first person to spot this problem with Attendance in v2.5.1.