OSError: dlopen(libSystem.dylib, 6): image not found

I suspect (but can't confirm) the System Integrity Protection (SIP) of OSX El Capitan is preventing access to your /usr/lib folder.

It would be extreme and defeating the purpose of the security feature, but you could try disabling SIP by booting into the OS X Recovery partition, executing csrutil disable and rebooting...atleast until another option / work-around can be found.

ArsTechnica has a write-up here: http://arstechnica.com/apple/2015/09/os-x-10-11-el-capitan-the-ars-technica-review/9/

And a similar issue is described here: http://blog.honekamp.net/blog/2015/09/07/el-cap-and-my-printer/

More discussion on Hacker News here: https://news.ycombinator.com/item?id=10309576

pip install --upgrade billiard
pip install --upgrade celery
pip install --upgrade kombu
pip install --upgrade amqp

This should work.

I uninstall "billiard,celery,kombu,amqp" those four packages. Then reinstall the latest version from github solved this