Getting "You must enter a name" and "Cannot focus a disabled or invisible window" on some machines with hidden UserInfoPage Inno Setup page

I have made a quick installer and in some PC I have found problems when installing. I have "serial number" system and when I press "Next" it gives me an error

You must enter a name

and then:

Cannot focus a disabled or invisible window

But in many other PCs with same SO this works normal. This is the code that I am using:

[Setup]
WizardStyle=modern
UserInfoPage=yes

[Code]

procedure CurPageChanged(CurPageID: Integer);
begin  
  if CurPageID = wpUserInfo then begin  
    WizardForm.UserInfoOrgLabel.Hide();
    WizardForm.UserInfoOrgEdit.Hide();
    WizardForm.UserInfoNameLabel.Hide();
    WizardForm.UserInfoNameEdit.Hide();
  end;
end;

// Presence of the CheckSerial event function displays the serial number box.
// But here we accept any non-empty serial.
// We will validate it only in the NextButtonClick,
// as the online validation can take long.
function CheckSerial(Serial: String): Boolean;
begin
  Result := (Serial <> '');
end;

function NextButtonClick(CurPageID: Integer): Boolean;
var
  WinHttpReq: Variant;
  Url: string;
begin
  Result := True;
  if CurPageID = wpUserInfo then
  begin
    WinHttpReq := CreateOleObject('WinHttp.WinHttpRequest.5.1');
    Url := 'Link that i use to check the serial number' +
           WizardForm.UserInfoSerialEdit.Text;
    WinHttpReq.Open('GET', Url, False);
    WinHttpReq.Send('');
    // Depending on implementation of the server,
    // use either HTTP status code (.Status)
    // or contents of returned "page" (.ResponseText)
    // Here we use the HTTP status code:
    // 200 = serial is valid, anything else = serial is invalid,
    // and when invalid, we display .ResponseText
    Result := (WinHttpReq.Status = 200);
    if not Result then
      MsgBox(WinHttpReq.ResponseText, mbError, MB_OK);
  end;
end;