Install: Database setup problem on OS X Server 10.5.8

I’m installing the ‘latest’ piwik on OS X Server Leopard 10.5.8, but am stuck on the “Database setup” page.

Note: The earlier page shows I have PDO, GD, PHP5.3.0, etc. all present and checked off, so it should be ready to go.

For ‘mysql server’ I’m using ‘localhost’ (if I try using my IP address, it times out)
For ‘login’ I’m using ‘root’ (and its password, but same error if I use ‘mysql’)
For ‘database name’ I’m using "piwik’ (which I’ve already created)
For ‘table prefix’ I’m using ‘piwik_’ (this is arbitrary)
For ‘adapter’ I’m using ‘MYSQLI’ (although PDO_MYSQLI gives the same error)

When I click on Go! I get the following nasty error:

PDO::__construct(): [2002] Invalid argument (trying to connect via unix://)
in ‘/Library/WebServer/Documents/piwik/libs/Zend/Db/Adapter/Pdo/Abstract.php’ at the line 129

#0 Piwik_ErrorHandler(2, PDO::__construct(): [2002] Invalid argument (trying to connect via unix://), /Library/WebServer/Documents/piwik/libs/Zend/Db/Adapter/Pdo/Abstract.php, 129, Array ([dsn] => mysql:host=localhost;dbname=piwik;port=3306,[q] => ))
#1 PDO->__construct(mysql:host=localhost;dbname=piwik;port=3306, root, xxx, Array ()) called at [/Library/WebServer/Documents/piwik/libs/Zend/Db/Adapter/Pdo/Abstract.php:129]
#2 Zend_Db_Adapter_Pdo_Abstract->_connect() called at [/Library/WebServer/Documents/piwik/libs/Zend/Db/Adapter/Pdo/Mysql.php:96]
#3 Zend_Db_Adapter_Pdo_Mysql->connect() called at [/Library/WebServer/Documents/piwik/core/Db/Pdo/Mysql.php:30]
#4 Piwik_Db_Pdo_Mysql->getConnection() called at [/Library/WebServer/Documents/piwik/core/Piwik.php:1473]
#5 Piwik::createDatabaseObject(Array ([host] => localhost,[username] => root,[password] => ********,[dbname] => piwik,[tables_prefix] => piwik
,[adapter] => MYSQLI,[port] => 3306)) called at [/Library/WebServer/Documents/piwik/plugins/Installation/Controller.php:153]
#6 Piwik_Installation_Controller->databaseSetup() called at [/Library/WebServer/Documents/piwik/plugins/Installation/Installation.php:62]
#7 Piwik_Installation->dispatch(Piwik_Event_Notification Object ([_notificationName] => FrontController.NoConfigurationFile,[_notificationObject] => Exception Object ([] => The configuration file /Library/WebServer/Documents/piwik/config/config.ini.php has not been found.,[] => ,[] => 0,[] => /Library/WebServer/Documents/piwik/core/Config.php,[] => 110,[] => Array ([0] => Array ([file] => /Library/WebServer/Documents/piwik/core/Piwik.php,[line] => 1574,[function] => init,[class] => Piwik_Config,[type] => ->,[args] => Array ()),[1] => Array ([file] => /Library/WebServer/Documents/piwik/core/FrontController.php,[line] => 202,[function] => createConfigObject,[class] => Piwik,[type] => ::,[args] => Array ()),[2] => Array ([file] => /Library/WebServer/Documents/piwik/index.php,[line] => 90,[function] => init,[class] => Piwik_FrontController,[type] => ->,[args] => Array ())),[] => ),[_notificationInfo] => Array (),[_notificationState] => 0,[_notificationCount] => 0))
#8 call_user_func_array(Array ([0] => Piwik_Installation Object ([] => Piwik_Installation_Controller),[1] => dispatch), Array ([0] => Piwik_Event_Notification Object ([_notificationName] => FrontController.NoConfigurationFile,[_notificationObject] => Exception Object ([] => The configuration file /Library/WebServer/Documents/piwik/config/config.ini.php has not been found.,[] => ,[] => 0,[] => /Library/WebServer/Documents/piwik/core/Config.php,[] => 110,[] => Array ([0] => Array ([file] => /Library/WebServer/Documents/piwik/core/Piwik.php,[line] => 1574,[function] => init,[class] => Piwik_Config,[type] => ->,[args] => Array ()),[1] => Array ([file] => /Library/WebServer/Documents/piwik/core/FrontController.php,[line] => 202,[function] => createConfigObject,[class] => Piwik,[type] => ::,[args] => Array ()),[2] => Array ([file] => /Library/WebServer/Documents/piwik/index.php,[line] => 90,[function] => init,[class] => Piwik_FrontController,[type] => ->,[args] => Array ())),[] => ),[_notificationInfo] => Array (),[_notificationState] => 0,[_notificationCount] => 0))) called at [/Library/WebServer/Documents/piwik/libs/Event/Dispatcher.php:213]
#9 Event_Dispatcher->addObserver(Array ([0] => Piwik_Installation Object ([] => Piwik_Installation_Controller),[1] => dispatch), FrontController.NoConfigurationFile) called at [/Library/WebServer/Documents/piwik/core/PluginsManager.php:363]
#10 Piwik_PluginsManager->addPluginObservers(Piwik_Installation Object ([] => Piwik_Installation_Controller)) called at [/Library/WebServer/Documents/piwik/core/PluginsManager.php:250]
#11 Piwik_PluginsManager->loadPlugins() called at [/Library/WebServer/Documents/piwik/core/PluginsManager.php:165]
#12 Piwik_PluginsManager->setPluginsToLoad(Array ([0] => CorePluginsAdmin,[1] => CoreAdminHome,[2] => CoreHome,[3] => API,[4] => Widgetize,[5] => LanguagesManager,[6] => Actions,[7] => Dashboard,[8] => Referers,[9] => UserSettings,[10] => UserCountry,[11] => VisitsSummary,[12] => VisitFrequency,[13] => VisitTime,[14] => VisitorInterest,[15] => ExampleAPI,[16] => ExamplePlugin,[17] => ExampleRssWidget,[18] => ExampleFeedburner,[19] => ExampleRssWidget,[20] => Provider,[21] => Feedback,[22] => Login,[23] => UsersManager,[24] => SitesManager,[25] => Installation)) called at [/Library/WebServer/Documents/piwik/core/FrontController.php:209]
#13 Piwik_FrontController->init() called at [/Library/WebServer/Documents/piwik/index.php:90]

Can anyone shed light on this? I don’t know how to proceed.
Thanks!
Tessera

By “latest”, do you mean 0.4.5 or from svn?

I’m using 0.4.5, downloaded from the piwik.org main page link.