http://resource.liandri.eu/download/darkbasic%20professional.zip
Unzip to any Folder
Run Launch.exe (main directory) or DBPEditor.exe (editor directory)
Tools > Options > Set Compiler Directory [UnzipDirectory]\Compiler\DBPCompiler.exe
Tools > Rebuild Keywords
And... you're all set.
Now as a quick note., there are some issues with running it on Windows 8.0, 8.1 or 10.0 64bit … mainly because it's a 32bit Codebase with 64bit 'extensions' that were added sometime after fully support ceased (somewhat as an afterthought).
All of the 64bit Variables work "As-Intended" but the others., well they exhibit some interesting and funky behaviour.
It's something I plan to look into when I have time.