I have the same problem on one of my machines.
I have done quite a lot of python development on this machine and installed many development versions of python libraries, for instance pyGtk - and I see that the upgrade scripts are written in python, perhaps this is the problem?
I have the same problem on one of my machines.
I have done quite a lot of python development on this machine and installed many development versions of python libraries, for instance pyGtk - and I see that the upgrade scripts are written in python, perhaps this is the problem?