Hi,
Testing out the plugin (version 2.3.9) on a WAMP server with Moodle 2.9, I was getting a whitescreen/PHP error when trying to add a User Field Search Box filter:
PHP Fatal error: Call to a member function get_columns() on a non-object in C:\Moodle\blocks\configurable_reports\components\filters\fsearchuserfield\form.php on line 41
Here's line 41 from that file:
$columns = $remoteDB->get_columns('user');
After doing some comparison, I noticed that the $remoteDB global is actually $remotedb in the other filter form.php files. Switching the three instances of the variable to all lowercase ($remotedb) in the fsearchuserfield/form.php file seemed to fix the problem.
HTH,
Matt