Is exactly this the software we are talking about?
https://winworldpc.com/product/delphi/3x
The error you are reporting happens on a 64 bit Windows but the installation should work flawlessly on a 32 bit Windows.
Anyway you should be able to install it also on 64 bit Windows but you need to follow this guide.
The Delphi 3 Client/Server installer include a 16-bit setup launcher, even though the Delphi 3 IDE and compiler themselves are 32-bit.
This was a common setup with InstallShield 5.x or older, where the stub loader was 16-bit to support both old and new systems.
WineVDM (OTVDM) can help you run the Delphi 3 installer on 64-bit Windows, because the installer uses a 16-bit stub like "setup.exe".
That stub fails to run on 64-bit Windows with a "This app can’t run on your PC" or "unsupported 16-bit application" error.
WineVDM (OTVDM) can intercept and run that 16-bit launcher, which may then spawn a working 32-bit setup process.
- download WineVDM (OTVDM) from GitHub: https://github.com/otya128/winevdm/releases
- extract it in C:\OTVDM\
- locate the various setup.exe you need to install
- create a shortcut to every setup.exe you need to install
- edit every shortcut, put C:\OTVDM\otvdm.exe at the left, something like this:
C:\OTVDM\otvdmw.exe "E:\Install\Delphi\Borland Delphi Client Server Suite 3.0\INSTALL\SETUP.EXE"
- save the modified shortcut and run it
Don't do that for install.exe in the root installation folder.
This helps launching the installers and once the real setup runs (which is 32-bit), your Windows system should handle it natively.
Delphi then should run natively because it is a 32 bit app, fully supported in 64 bit Windows.
I use it successfully with Windows 11 Pro 64-bit running MS Foxpro for Windows 2.6a and MS Money 2000, both from 1998/1999.
(Please read my comments/answers online because often I update/correct them!)