your problem comes from the fact that your folder must be named "SilentHunterIII" or 'SilentHunter3' during the installation c is said you must follow what is simply said
With v15 set up, didn't have to. I named the main folder that SH3 was set up for that, as 'LSH3-2015'... which I figured LSH3-v20 would be sufficient... *sighs*