I just got this report from a user:

I keep getting the following error from time to time when I submit a post. Unfortunately it deletes what I have typed and I have to start again :-(

It can happen even if I have posted successfully just a few minutes earlier.

Error: 0 - Invalid controller: name='rating', format=''

(this error is on top of the default 404 page)

** I have seen something similar from time to time (very rare, but once in a while) when posting as admin...

any hints on how to fix?  nothing obvious showing in the error logs...