build.xml is made to work with development environment, so it's better to clone whole repository to be able to run phing, however copying build.xml and tests folders should work as well.

Unable to find property file: path_to_una\build.properties.

build.properties isn't required, so this isn't error but a notice.

When you run phing without params (for example: php phing-latest.phar) then default target is run which is running phpunit tests. To package module you need to pass additional parameters as described in the documentation.