Database error when using DB table prefix in Drupal config

I entered a DB table prefix at the installation of Drupal since I have more than one Drupal installation in a single DB.

This module however has the table "user" hardcoded into the sql-query instead of looking for a table prefix in the configuration, resulting in not being able to access the table "user". So I got an error message from Drupal not being able to access that table.

I corrected this in the modules code for me locally but I think the code should be altered accordingly.