When network connectivity issues prevent any version of InDesign or InCopy from reading from or writing to open files, it performs a protective shutdown.
The shutdown can appear to be an application crash or unexpected quit. However, it is intentional behavior to protect from data loss.
I am having the exact same problem on a iMac (late 2013) running 10.10.1 and Indesign Creative Cloud 2014. Working on any Indesign file residing on the server, then trying to export a PDF will crash (like the OP - "The network connection was lost...") about 50% of the time.
However, I also have Indesign CS6 running on the same machine and it has never exhibited this problem. I open files off the server, work on them, export out PDFs with nary a hitch.
There is definitely something an issue with Indesign CC 2014 that is not present on previous versions.
March 2016- It still exist. (InDesign Creative Cloud 2015.2 - Mac El Capitan 10.11.3, iMac Late 2015)
It's flawed by design: https://helpx.adobe.com/indesign/kb/crash-lost-network-connection.html
I would love to see crash-report statistics about this issue... I'll send them multiple times a day.
Isn't it possible to use Apple's Power Nap to use the network while the computer is at sleep?
I've been looking for a solution for over a year, and the best explanation for why this is still an issue is that Adobe already has our money.