I think this is the problem. When you use Ascii(), it returns what basically is an array pointer in C. You have to manually free the array since there is no garbage collector to clean up the heap.
I picked up a copy of PureBasic many years ago and used it a few times for writing quick tools, since BASIC (Locomotive, ST, and GFA) was my first family of languages, and I sometimes get sentimental. It is still developed and actually a really nice implementation. But like /u/insertAlias wrote, in terms of commercial viability and "popularity", VB is where it's at.
Now it is PureBasic (https://www.purebasic.com/). It is very code centric, which appeals to my taste. Here (https://ricardo-sdl.itch.io/) you can check the games I created using it, also includes the source code.