Alpha user points doesn't exist anymore. There is a new version with the name: Alta User Points. When you update Alpha User Points to Alta User Points and you totaly delete Alpha User Points, your plugin from Ariquiz doesn't work anymore.
Here is how you can fix it:

go to: plugins/system/ariquizalphauserpoints
open: ariquizalphauserpoints.php
go to: line 70
change: AlphaUserPointsHelper to AltaUserPointsHelper
go to: line 86
change: components/com_alphauserpoints/helper.php to components/com_altauserpoints/helper.php

Hello,

We have added plugin for integration with AltaUserPoints extension. It is available here on "Files" tab.

Regards,
ARI Soft