I had the exact same issue and couldn't find a solution. I was going round in circles trying to figure out what on earth was going wrong.
I finally came across this post:
Fatal error: Cannot override final method
You need to make sure that the apc.include_once_override
setting is set to 0. In your apc.ini file set like so:
apc.include_once_override=0
This error seems to be caused by caching of included classes.