Need help with Amakano Perfect Edition.

[Illusion1605]

Hello, people.
Got Amakano Perfect Edition and an update to it. The game works fine, yet I cannot install the update. Says "The game is not installed". Tried to find info or ask people, no luck.
Is there a kind soul to explain me the way to install that bloody update?

 

[Illamng]

It is a re-release of the game and not an update
Then you should install