I cannot reproduce this error.
Installed on 3.8.8, working fine.
Were you getting this error before making the changes above?

I was afraid you'd say something like that!
I don't know... I don't specifically remember using the "View all posts by..." between the time I installed the plugin and the time I moved it to global_start. I think I did, but I'm not sure.

I guess I need to do some more investigating... I'll move it back to the hook its intended to use (if I can remember which it is) and see what happens.

--don

I am not using the code that you posted, I am using what I posted.

I tried to view all post by the user that made a post in one of my subscribed threads, no errors.
I viewed all my post from postbit where the subscribed thread post was made, no errors.

I changed the plugin location to where it was, no errors.

Maybe something else is causing that error.

Try disabling all plugins and turn each back on one by one until you see the error.

I remember the first time I was told that and I had way to many addons installed, it took me a little why until I found my issue.