There is a bug with the User and Swimmer reports which will manifest itself when either the User or Swimmer optional field count is set to zero AND the table where the optional fields are stored is completely empty. I have fixed the bug and checked it but am not quite ready to do a release due to some other changes I am in the process of making not being finished yet. The bug will also manifest itself when trying to export a list of users or swimmers as CSV.
If you run into this problem, let me know – there is a fairly easy work-around that will prevent it from happening.