I don't know of a single system on which python passes its self-check. I would suggest unsetting SAGE_CHECK and trying "make" again. (Or unset SAGE_CHECK and install just the python package by typing "./sage -i spkg/standard/python-2.6.4.p9.spkg". Once that's done, you can do "export SAGE_CHECK=yes; make" again to build the rest of Sage.)