Could this be a reason why it’s not opening on my windows 10 laptop ??

Sorry, I thought you were talking about Linux. You could make Kolourpaint work in Windows through some WSL, but it’ll be probably too much of a bother.

For Windows I hear a lot of people talking about Paint.NET. It is not open source. You could also try Krita, also from KDE; unlike Kolourpaint it has a native Windows version, but it’s a bit more advanced (usually when people ask for a Paint equivalent they want something simple).