Error on .../blogs-mu/functions.php on line 129

Hi all,
I just installed both the Blogs MU Theme and the Blogs MU Child Theme.
For my main site I activated the Blogs MU Child Theme.
What I get under the footer is:

Fatal error: Call to undefined function get_network_home_url() in .../wp-content/themes/blogs-mu/functions.php on line 129

I use it on a fresh Wordpress 3.1.3, multisite with NO BuddyPress installation.
Both themes are only activated on the main site.

Any suggestions? Thank you.

Bonus questions:
1. Is there a manual on how to configure the specific (Blogs MU) theme? With /out BuddyPress.
2. Especially the page templates. I must say I got confused on when/how to use Blog and News/ Members login templates or even if
3. I should have a static page as the Home page and a different one for the posts. Actually, I will NOT have any posts since this is my main network area. So how do I handle that?
Thanx again.