#1 Failure when local repository points unreadable member

[SSM]

When a local url (e.g., file:/... or /...) is passed to
the repository object, and one of the members (spec. a
directory) that is unreadable, the
os.walk(baseUrl).next() call fails with a StopIteration
exception.

This and the following two lines should be enclosed in
a try/except.