I had same issue with python 2.5 / mac os 10.5.6 / openerp 5.0.0 .
I played with adding this line just before the xpath import "from xml.utils import boolean" and with doing an "export PY_USE_XMLPLUS=YES" before starting openerp. It worked then.
Maybe it can help in python 2.6 too. Can you let me know ?
I had same issue with python 2.5 / mac os 10.5.6 / openerp 5.0.0 .
I played with adding this line just before the xpath import "from xml.utils import boolean" and with doing an "export PY_USE_XMLPLUS=YES" before starting openerp. It worked then.
Maybe it can help in python 2.6 too. Can you let me know ?