Magento su altervista. non funziona

Ciao a tutti, ho effettuato il check di controllo che da all'inizio dell'installazione di magento ma mi da questo errore:

Step 1: Readiness Check

Error! You need to resolve these issues to continue.
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PHP Documentation
PHP Version Check
Your PHP version is . The required PHP version is . Hide detail

Download and install PHP from www.php.net using this PHP Documentation.

For additional assistance, contact your hosting provider.

PHP Settings Check *
Your PHP settings are correct.

Cannot determine required PHP extensions: The HOME or COMPOSER_HOME environment variable must be set for composer to run correctly
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PHP Extension Help
PHP Extensions Check
missing PHP extensions. Hide detail

The best way to resolve this is to install the correct missing extensions. The exact fix depends on our server, your host, and other system variables.
Our PHP extension help can get you started.

For additional assistance, contact your hosting provider.

File Permission Check
You meet 4 out of 4 writable file permission requirements. Show detail

* - In some cases, you might have two PHP configuration files: one for the PHP command line and for the web server. If so, make the change in both php.ini files. For details, see the php.ini reference.

Qualcuno sa come risolvere?

Interessa anche a me.

Qui ci sono i requirements di magento:
http://devdocs.magento.com/guides/v2...ents-tech.html

e questi sono gli errori che mi vengono segnalati dall'installer di magento:



Spero che presto AV possa diventare 100% compatibile con magento, sarebbe una gran bella cosa per tutti noi!
Grazie.