I've come across this error whenever I try to move around the layers on an edge project. As a result the edge animate .an file becomes corrupt and I cannot go back to the file.
Some more notes:
I created a new file in Edge Animate using the 2014 October update.
I've removed any external scripts.
I'm use web fonts.
Is it possible to share the project files with us? Would help to repro this issue on our side and trouble shoot.
Edge Animate Team