Understanding the different DEB packages

Just to get this out of the way, I didn't think this belonged in a beginner's thread, but I wasn't sure where else to post it. So if it would be better suited somewhere else, please feel free to move it.

In Book 1of the learning series provided with GambOS, Introduction to GambOS, gbWilly explains in great detail in Chapter 2.2, “Debian Package Management,” how to create DEB packages.

Among other things, you'll find this note there.

Warning:

A .deb package created in the Gambas IDE from your application on a system running an official Debian/Ubuntu repo Gambas version, will work on a system running the OSB Gambas or GambOS repo version of Gambas.

The other way around is not always true, depending on dependencies required by the package. This can cause trouble when distributing your applications as .deb packages to systems running Debian/Ubuntu official Gambas version as they might lack the installation packages required (for example gambas3-dev-tools).

I hadn't really stopped to think about what that actually means until now. So, does that mean the packages can't be installed, or does it cause errors?

I've just discovered something very strange.
A DEB package built on Ubuntu actually runs fine on my computer, but a media file that the program automatically opens after a certain amount of time won't play. So either the file isn't included with the program, or it can't be accessed.
When I build the package myself on my Devuan machine from the source files in my IDE, it works differently.
A quick look at the build logs shows me that, for one thing, different versions of GCC are being used, but more importantly, in my opinion, Devuan uses dBus packages while Ubuntu uses systemd packages.  So maybe the drives are being addressed completely differently, and that’s why the file can’t be found???

My question is: could these differences in the systems be responsible for this, or could it be that the media file is not included during package creation for some reason?

How can I avoid such problems? Can I explicitly select which files should be included, and shouldn’t this actually be the case automatically for all files in the Gambas Applications folder?