I solved the problem:
in the page: Admin/user_result.php you have to chenge in the line 302 and 303 the code with this below.
<input type="button" name="view_user" id="view_user" value="View Details" onClick="window.location = 'users_detail.php?UserID=<?php echo(rawurlencode($row_WADAusers['UserID'])); ?>'" class="ps_buttons" />
<input type="button" name="update_user" id="update_user" value="Update User" onClick="window.location = 'users_update.php?UserID=<?php echo(rawurlencode($row_WADAusers['UserID'])); ?>'" class="ps_buttons" />