problem installing pygraphviz in sage 6.2

edit

I'm trying to install the python package pygraphviz in sage 6.2 through the following procedure.

sage -i dot2tex
sage -i graphviz
sage -sh <<< "easy_install --verbose pip"
sage -sh <<< "pip --verbose install pygraphviz"

The first three commands are successful. The last one, however, outputs the following. Any help will be appreciated. Thanks.

Starting subshell with Sage environment variables set.  Don't forget
to exit when you are done.  Beware:
 * Do not do anything with other copies of Sage on your system.
 * Do not use this for installing Sage packages using "sage -i" or for
   running "make" at Sage's root directory.  These should be done
   outside the Sage shell.

Bypassing shell configuration files...

Note: SAGE_ROOT=/home/soft/sage/sage-6.2-i686-Linux
Traceback (most recent call last):
  File "/home/soft/sage/sage-6.2-i686-Linux/local/bin/pip", line 9, in <module>
    load_entry_point('pip==1.5.6', 'console_scripts', 'pip')()
  File "/home/soft/sage/sage-6.2-i686-Linux/local/lib/python2.7/site-packages/setuptools-2.0.1-py2.7.egg/pkg_resources.py", line 352, in load_entry_point
  File "/home/soft/sage/sage-6.2-i686-Linux/local/lib/python2.7/site-packages/setuptools-2.0.1-py2.7.egg/pkg_resources.py", line 2295, in load_entry_point
  File "/home/soft/sage/sage-6.2-i686-Linux/local/lib/python2.7/site-packages/setuptools-2.0.1-py2.7.egg/pkg_resources.py", line 2009, in load
  File "/home/soft/sage/sage-6.2-i686-Linux/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/__init__.py", line 10, in <module>
    from pip.util import get_installed_distributions, get_prog
  File "/home/soft/sage/sage-6.2-i686-Linux/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/util.py", line 15, in <module>
    from pip.locations import site_packages, running_under_virtualenv, virtualenv_no_global
  File "/home/soft/sage/sage-6.2-i686-Linux/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/locations.py", line 96, in <module>
    build_prefix = _get_build_prefix()
  File "/home/soft/sage/sage-6.2-i686-Linux/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/locations.py", line 65, in _get_build_prefix
    __get_username())
  File "/home/soft/sage/sage-6.2-i686-Linux/local/lib/python2.7/site-packages/pip-1.5.6-py2.7.egg/pip/locations.py", line 60, in __get_username
    return pwd.getpwuid(os.geteuid()).pw_name
KeyError: 'getpwuid(): uid not found: 2006'
Exited Sage subshell.