I downloaded Exitilus v3.17 on to a Win x64 system; but both the INSTALL.exe and EXSETUP.EXE can't be run under this operating system
(I'm guessing it's 16bit). I also tried running StarFight on this
system but the main binary couldn't run.
Is it possible to run these doors under a Mystic x64 BBS?
There is a windows_door_install that talks about this stuff and goes over some options, although it doesn't talk about using DosBox which some have tried.
In general though, Microsoft Windows cannot run DOS programs in its 64-bit version. Its not a Mystic thing, its a Windows thing in this case. 32-bit Windows up to Windows 10 can still run DOS programs and Mystic will run them in the same way you'd set them up in DOS.
There is some effort by some to hack a DOS emulator for Windows 64 that is mentioned in the windows_door_install.txt in the docs folder in the latest version and you can try to do that, or you can run 32-bit Windows, or you can try DosBox (although I have little to no experience with the latter because it doesn't work well with multiple nodes)
... Read messages, not taglines
--- Mystic BBS v1.12 A47 2021/11/24 (Windows/64)
* Origin: Sector 7 * Mystic WHQ (1:129/215)