Phing error when using gitclone - Git tasks depend on PEAR\'s VersionControl_Git package

When I run phing install i keep getting this error:

Execution of target "install" failed for the following reason:
/Applications/MAMP/htdocs/wp-test/build.xml:7:8:
/Applications/MAMP/htdocs/wp-test/build.xml:7:8: The Git tasks depend 
on PEAR\'s VersionControl_Git package.

So I download the package:

downloading VersionControl_Git-0.4.4.tgz ...
Starting to download VersionControl_Git-0.4.4.tgz (14,831 bytes)
.....done: 14,831 bytes
install ok: channel://pear.php.net/VersionControl_Git-0.4.4

But still it gives me the same error. This is my build.xml:

<project name="wp-dev" default="install">
    <property name="package" value="wp-dev" override="true"/>
    <property name="wpdeposit.dir" value="wp-content/plugins/wpdeposit" override="true"/>
    <target name="install">
        <gitclone
                repository="https://github.com/WordPress/WordPress.git"
                targetPath="/" />
    </target>

</project>

Solution

You need to setup PHP's include path, see the PEAR manual for more information.