Getting 502 bad gateway on uploading a file

[Michael Shadle]

Trying to upload a small .png to Drupal. PHP 5.3.8, CentOS 5.6 x64, nginx 1.1.3

Everything else seems to work fine, but can't seem to get any deeper
information as to why anything is getting messed up. Not sure if the
debug log has any hints or not.

(note I also tried nginx 1.0.8) - does this debug log help with
anything? or is this "probably PHP"?

http://pastebin.com/E1kDBegW

Thanks