Die early if CreateDialog fails

src/arch/LoadingWindow/LoadingWindow_Win32.cpp

@@ -146,6 +146,7 @@ LoadingWindow_Win32::LoadingWindow_Win32()
 {
 	m_hIcon = NULL;
 	hwnd = CreateDialog( handle.Get(), MAKEINTRESOURCE(IDD_LOADING_DIALOG), NULL, WndProc );
+	ASSERT( hwnd != NULL );
 	for( unsigned i = 0; i < 3; ++i )
 		text[i] = "ABC"; /* always set on first call */
 	SetText( "" );