I have a similar problem with a very similar message. The message I get is the following:
At line 73 of file "OptimizeGraphics.jsfl":
I'm running Animate cc 2015.2 on a Mac and I cannot locate the files mentioned in the solution. Are there other solutions or can these files, "Exporter.jsfl" and "ContainerSymbol.jsfl" be somewhere else or with a different name?
I am able to download the files on my computer. What happens when you try to download these files?