Thanks, no luck with WINE and while I'm sure writing a converter would be possible, it is as you mentioned quite a lengthy and somewhat difficult task, especially considering how different OpenGL and Dark BASIC are.
Anyway, I've ended up re-writing my code in OpenGL by hand. I was quite surprised how easy it was to learn OpenGL after having learned DarkBASIC. The only real problem being that it's purely a graphics API, so I'm going to have to learn something else to add sound and music into my games. Maybe I'll learn OpenAL too.
Hey! It compiles! Ship it!