Weird behavior of filtering fields of profile.

Hi,
I am using Drupal 5.1.
After installing the 5.x-1.x version of this module and configured it so that about 10 fields of my profile would show up to filter the user listing, I am getting this:

one field (text field) shows a drop down menu with either "blocked" or "active" inside.
Another field (selection list) shows the second option only.
A third field (selection list) shows the first option only.

Any idea what I can do to correct this?

Thanks
Michael