Mostly all computer languages are good for learning about the way that computers work. But if you want to write a program to port scan, exploit vulnerabilities, or process files for you, a game programming language isn't the only thing you need to learn. Years ago, I learned GML (Game Maker Language) and programmed many prototypes for various games in it. Later on, when I started learning C++ and Java, I realized how stupid and pointless GML was and I now never use GML except to play around with game concepts. Although I'm not saying that Dark Basic is a bad language, what I'm saying is that it isn't a suitable language to do everything in.
I recommend for you to move onto another language and learn it well. Try learning Basic if it is similar to Dark Basic. Then try moving onto C++ and Java. Those are the two most dominant languages out there right now. Java is a very fun, simple, and powerful language with cross-platform capabilities. C++ on the other hand, is a very complex and very powerful language. C++ in my opinion is better simply because it has a much greater library of stuff to use. You name it, and it has already been done in C++ before. Servers, databases, client applications, services, games, even other languages. Perl and Lua are two very high level languages built on top of C (C and C++ are almost the same thing).
As a wise centipede once said: "google is your friend"
Good luck to you!