CI_Log error

Ok, but I just do the update and the problem appeared immediately afterwards.
I don't know to what to look for now to debug.

I had the exact same message.

Check your overridden function parameters. I chased my tail for 1/2 hour and then realised I was missing $level, $msg in my write_log function parameters.    


Also don't forget you can't just assume the super object is available (for reference) when overriding CI_log.