Thread:Project:Support desk/Error when trying to install MediaWiki 1.20.2

Here is the message that I get:

Warning: Cannot modify header information - headers already sent in C:\xampp\htdocs\wiki\includes\Exception.php on line 269

Warning: Cannot modify header information - headers already sent in C:\xampp\htdocs\wiki\includes\Exception.php on line 270

Warning: Cannot modify header information - headers already sent in C:\xampp\htdocs\wiki\includes\Exception.php on line 229 A database query syntax error has occurred. This may indicate a bug in the software. The last attempted database query was: CREATE DATABASE `my_wiki` from within function "MysqlInstaller::setupDatabase". Database returned error "1044: Access denied for user ''@'localhost' to database 'my_wiki' (localhost)". Backtrace:
 * 0 C:\xampp\htdocs\wiki\includes\db\Database.php(916): DatabaseBase->reportQueryError('Access denied f...', 1044, 'CREATE DATABASE...', 'MysqlInstaller:...', false)
 * 1 C:\xampp\htdocs\wiki\includes\installer\MysqlInstaller.php(469): DatabaseBase->query('CREATE DATABASE...', 'MysqlInstaller:...')
 * 1) 2 [internal function]: MysqlInstaller->setupDatabase(Object(MysqlInstaller))
 * 3 C:\xampp\htdocs\wiki\includes\installer\Installer.php(1454): call_user_func(Array, Object(MysqlInstaller))
 * 4 C:\xampp\htdocs\wiki\includes\installer\WebInstallerPage.php(1161): Installer->performInstallation(Array, Array)
 * 5 C:\xampp\htdocs\wiki\includes\installer\WebInstaller.php(269): WebInstaller_Install->execute
 * 6 C:\xampp\htdocs\wiki\mw-config\index.php(50): WebInstaller->execute(Array)
 * 7 C:\xampp\htdocs\wiki\mw-config\index.php(18): wfInstallerMain
 * 1) 8 {main}

Can you help me?