Upgrade (to 0.9.3) hangs

Dear developers,

I encounter a misterious problem during the upgrade of a site.

I try to upgrade a site from Silva 0.9.1 to Silva 1.0. All goes well in the
first step which calls the Silva upgrade092.py. Then the next upgrade step
starts calling the Silva script upgrade093.py. Suddenly the upgrade stops
without any error message.
The last message printed out was:
Upgrading object http://foo/silva_ethz/ETH/imprint (still 130 objects to go)
Setting title to: u'Impressum'

I then killed the python processes, re-installed the initial Silva 0.9.1
instance, and started the upgrade process again. The upgrade blocks after
displaying exactly the same message. I again re-installed the Zope instance,
started it and removed the indicated object. After starting the upgrad, the
process blocks again, this time on a different object, e.g.:
Upgrading object http://foo/silva_ethz/ETH/xyz (still 130 objects to go)
Setting title to: u'XYZ'

After re-installing the original site and removing the specified object and
restarting the upgrade, again the process block after indicating that it has
still 103 objects to go.

Any ideas?

Regards,
Benno

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Benno Luthiger
WEP J 11
Swiss Federal Institute of Technology Zurich
CH-8092 Zurich

Tel: +41 1 632 57 65
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