Upload piwik and see error

Im new in forum and piwik. I do all in readme file and when i open in browser adress of my site i see:

Fatal error: require_once() [function.require]: Failed opening required ‘//core/testMinimumPhpVersion.php’ (include_path=’//core://libs://plugins’) in /index.php on line 40

I check via php info of minimal req and have all active.
What i ned to do to install script?

Are you using a chrooted jail for your web server?

I think the quick fix is to edit index.php and piwik.php, changing:

define('PIWIK_DOCUMENT_ROOT', dirname(__FILE__));


define('PIWIK_DOCUMENT_ROOT', dirname(__FILE__)=='/'?'':dirname(__FILE__));