Jenkins and django: "Cannot allocate memory" with popen from django-jenkins run

Question

I'm using jenkins to run my django tests, with django-jenkins

since a few days (without changing confs), when i run django-jenkins i get the error

OSError: [Errno 12] Cannot allocate memory

even if my tests pass.

the complete error (from jenkins) is here https://gist.github.com/apelliciari/5106439

In my test i have some LiveServerTestCase with Selenium.

Searching for the error, i've found these

Python subprocess.Popen "OSError: [Errno 12] Cannot allocate memory"

http://bramp.net/blog/2010/05/python-close_fds-issue/

Hope they are useful, unfortunately my knowledge of python/unix is not so deep, and i can't grok how to fix it.

Is there a way to run tests avoiding the forks? I don't care if they take more time.