That is an odd way to find out what OS Firebird supports, and it is not
correct IMHO.
The Firebird release notes should explicitly list the OS versions
supported, and the installer should work on those.
However, the installer script[1] has this comment:
"""
As per the innosetup documentation:
"Change in default behavior: [Setup] section directive MinVersion now
defaults to 6.1sp1, so by default Setup will not run on Windows Vista or
on versions of Windows 7 and Windows Server 2008 R2 which have not
been updated. Setting MinVersion to 6.0 to allow Setup to run on
Windows Vista is supported but not recommended - Windows Vista doesn't
support some of Setup's security measures against potential DLL
preloading attacks so these have to be removed by the compiler if
MinVersion is below 6.1 making your installer less secure on all
versions of Windows."
This change _may_ be a problem for W2K8 R2. In any case Windows Vista
and even Windows 7 are now deprecated and hopefully no production
install of W2K8 R2 is unpatched. If necessary we can define
'support_legacy_windows' to roll back this new feature but users who
need to deploy to what are now ancient versions of windows are advised
to manually install Firebird 4.0 with the zip package.
"""
Which suggests that if the OP is using Windows Server 2008, it won't
work, and must update to Windows Server 2008R2 with the latest updates.
[1]:
https://github.com/FirebirdSQL/firebird/blob/v4.0-release/builds/install/arch-specific/win32/FirebirdInstall.iss#L127
--
Mark Rotteveel