For what it’s worth…
I was having this exact problem with After Effects CC at render time. Running the Console app on my mac (applications- utilities- console) I noticed a crash report. According to that crash report- something had caused the Adobe QT32 Server to crash. A google search showed that blackmagic drivers could be a culprit- I had some blackmagic software on my machine. I downloaded their utility from the Blackmagic website (under support) in order to properly uninstall all of their drivers from my mac, and now AE renders beautifully again!
Long story short- there is more than likely something on your machine causing this type of crash- if you go into your activity monitor (applications-utilities-activity monitor) and select “My Processes” from the drop down menu at the top of the window- look for any 3rd party programs in the list. In my case- the culprit was titled “Desktop video driver updater” or something like that. I didn’t recognize it at first- but Desktop Video was the name of the Blackmagic software that was on my machine.
Note- I had been running Aftereffects cs5.5 with the blackmagic software on my computer with no issues- it wasn’t until I upgraded to AfterEffects CC that I started having issues at render time.
Good luck!
Will