The ispconfig interface part works fine on windoes, you just have to edit the database details in config.inc.php file. The file config.inc.php is the config file since the beginning of ispconfig 3, the other fiels you mentioned were added by a contributor and had been removed as they were not needed. I will delete the part of the tutorial.
Regarding the warnings that you get, either your enviroment is missing some php modules or the error_reposrting level is wrong. ISPConfig uses the level:
E_ALL & ~E_NOTICE