Warnings when installing on XAMPP

When I install NinjaBoard on XAMPP and Joomla 2.5.4 then I get many warnings at the login page (see below) and don´t know what to do. Can you please help?

Warning: Missing argument 1 for JLoader::register(), called in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 50 and defined in C:\xampp\htdocs\iono\libraries\loader.php on line 209

Warning: Missing argument 2 for JLoader::register(), called in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 50 and defined in C:\xampp\htdocs\iono\libraries\loader.php on line 209

Warning: array_key_exists() expects parameter 2 to be array, null given in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 51

Warning: Missing argument 1 for JLoader::register(), called in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 50 and defined in C:\xampp\htdocs\iono\libraries\loader.php on line 209

Warning: Missing argument 2 for JLoader::register(), called in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 50 and defined in C:\xampp\htdocs\iono\libraries\loader.php on line 209

Warning: array_key_exists() expects parameter 2 to be array, null given in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 51

Warning: Missing argument 1 for JLoader::register(), called in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 50 and defined in C:\xampp\htdocs\iono\libraries\loader.php on line 209

Warning: Missing argument 2 for JLoader::register(), called in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 50 and defined in C:\xampp\htdocs\iono\libraries\loader.php on line 209

Warning: array_key_exists() expects parameter 2 to be array, null given in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 51

Warning: Missing argument 1 for JLoader::register(), called in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 50 and defined in C:\xampp\htdocs\iono\libraries\loader.php on line 209

Warning: Missing argument 2 for JLoader::register(), called in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 50 and defined in C:\xampp\htdocs\iono\libraries\loader.php on line 209

Warning: array_key_exists() expects parameter 2 to be array, null given in C:\xampp\htdocs\iono\libraries\koowa\loader\adapter\joomla.php on line 51

php.ini was a good tip. I changed some parts into Off e.g. display_errors, display_startup_errors, error_reporting,html_errors. But that doesn´t help on my localhost. Then I changed the same at php.ini-development and the warnings disappeared.

Thanks donau