This error is shown by Windows if you attempt to run the 64-bit SyncBack installer on 32-bit Windows. Please download the 32-bit installer.
The error is also shown when trying to install on any version of Windows older than Windows 7 SP1 (Windows 2008 R2 SP1), e.g. Windows Vista or Windows 7 (or Windows 2008 R2) that does not have Service Pack 1 (SP1) installed.
This error may also be shown if you attempt to run SyncBack on Windows XP or Windows Server 2003, neither of which are supported. SyncBack is not supported on Windows Vista or Windows 7 (or Windows 2008 R2) that does not have Service Pack 1 (SP1) installed.