The TarFile constructor (as well as tarfile.open) takes an errorlevel
keyword argument. See
http://docs.python.org/dev/library/tarfile.html#tarfile-objects

I quote: "If errorlevel is 0, all errors are ignored when using
TarFile.extract(). Nevertheless, they appear as error messages in the
debug output, when debugging is enabled. If 1, all fatal errors are
raised as OSError or IOError exceptions. If 2, all non-fatal errors are
raised as TarError exceptions as well."

Hope that helps.