Oh, that repeating warning shouldn't be happening any more.
I had turned on visible errors in a futile attempt to try to debug something else.
I'm not sure about the content encoding error, though. That looks like a web browser error, not something php would have coughed up. Let me know if you see it again, and the search terms you were using.
On second thought, now that I think about it, those warnings themselves may have been triggering that first error, because they were probably sent before the rest of the page, when compression wasn't set up yet.
“The egg hatched...” “...the egg hatched... and a hundred baby spiders came out...” (blade runner)
“Who are you?” “A friend. I'm here to prevent you from making a mistake.” “You have no idea what I'm doing here, friend.” “In specific terms, no, but I swore an oath to protect the world...” (continuum)
“It's a goal you won't understand until later. Your job is to make sure he doesn't achieve the goal.” (bsg)