Credits: https://bugs.launchpad.net/openobject-addons/+bug/1008513/+index?ss=1

Symptoms:

After migration on Ubuntu 14.04, many of us experienced a problem that OpenERP server cannot start. As it was described in our blog here, OpenERP 6.1 doesn’t work with pywebdav version 9.8. The main reason why it doesn’t work is described into “the credits” article and because the method of import pywebdav library is changed for version 9.8.

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