Make sure you are using the Unicode version of Inno Setup.

I use the WinSCP-5.9.2-Source,and I want to build a WinSCP installer use inno setup.But wan i run isccwinscpsetup.iss ,it have a error: Type mismatch.error is in hear :WizardForm.ActiveControl := TWinControl(TControl(Sender).Tag);
all of code is :
procedure ImageClick(Sender: TObject);
begin
WizardForm.ActiveControl := TWinControl(TControl(Sender).Tag);
end;
can you help me.Think you!

Please read documentation:
https://winscp.net/eng/docs/custom_distribution#preconfigured_site

If that does not help, come back.

I want to pre-package an installer of WinSCP with the site pre-configured for SFTP and the key already setup. I know that you can do this using Inno Setup and it's supposed to be quite simple but I can't find any documentation on it. Is there a brief guide available that would help me accomplish this?

Thanks in advance