http://screencast.com/t/r5kOlIiHfH

After selecting Network, and selecting all the curves one by one, I don't get a shell on these curves. What I am I doing wrong? If it has any bearing, to construct this, I used Mirror on the various curves to get the symmetry and then Join.

Thanks.

edit: I tried adding more curves, and after some calculation time, I get a mess with twisted surfaces flying out.

edit: on close inspection, I see I have un-joined lines.

http://screencast.com/t/LGt5ac1f

http://screencast.com/t/S9jC5ueq

I'll try this again, but are there any tips about starting a line with its end point along another line? Or, in general, how to always get a good connection for any lines ?