Hi Scott - just a quick note about your attached file - that's not going to work with Network because the curves don't form a regular grid pattern - it almost does but not quite.

The top side is set up ok for network, with this one curve here:



But then instead of having curve set out for the left, right, and bottom areas of the network you've instead just got one single long curve running all the way through here:



That long curve that's wrapping around and touching both horizontal as well as vertical lines of the network means that it does not "unwrap" into a 2D pattern and so that curve arrangement won't work for Network.

Basically Network requires that the curves have a way to unwrap to a 2D grid, similar to the way that a flat rectangular map of the world is unwrapped from a 3D globe, where you have 2 sets of lines, one for longitude and one for latitude and although they can cross over each other it does not work to have lines of longitude and/or latitude having an endpoint all on one single curve like you have here.

See here for some more links with additional description on the kind of layout you need and some things to avoid:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4384.4


However, having said all of that for why Network is not working for you, I'm not really sure that Network is the best tool for what you show there - I'll post some other ideas separately.

- Michael