I have a similar error.
A colleague in a different location cannot upload – receives HTTP ERROR.
When I returned to my office my partner, a different person than referenced above, experienced the HTTP ERROR. We were both on the same router, using the same version of Chrome. he could not upload, but I could.
Then miraculously, she was able to upload images.
I did update server settings to PHP 5.4 (Even though that’s where they were already set.)
Any ideas?