Ok, somehow the database is out of sync with the installed version. The first thing that needs to be done is to update the database version. On the database, pleasa run this code:
UPDATE #__awocoupon_config SET value="3.5.7.0" WHERE name="AWOCOUPON_VERSION_DB"
Where #__ is your actual database prefix. Once you do this and refresh AwoCoupon, you will see it goes into a loop. Now find the file:
www/administrator/components/com_awocoupon/awocoupon_j3.xml, change the version line to this
<version>3.5.7.2</version>
And that should do it.