We have another thread discussing this issue at http://forums.adobe.com/message/5331743
But it is out of date and marked with a green-icon positive solution, so..
still I try to reopen the issue about an error of "Edge Animate could not find the associated html file"
for me, this error remains even after opening and saving corresponding html file.
in fact I don't remember any successful launch of .an file for all my projects
working at win 7, 64 bit
Can you post your project files for us to take a look at?
Does it help?