matplotlib and zope problem

Hello All,

  I've been using matplotlib for some time now, and I want to connect it
  with zope. I'am using the example code from page:
http://www.scipy.org/Cookbook/Matplotlib/Matplotlib_and_Zope ,
but whenever I try to import matplotlib, and/or pylab packages i get
this error from zope:

Error Type: RuntimeError
Error Value: '/' is not a writable dir; you must set environment
variable HOME to be a writable dir

Have You got any ideas, on what might go wrong? I'am using matplotlib
0.87.4, and zope 2.9.5 with python 2.4.3 on gentoo linux box.

Thanks in advance for any help.

Marek Szczypinski