Synaptic throws exception 'std::out_of_range'

Synaptic package manager supplied as part of Ubuntu 11.10 distribution.
Trying to launch Synaptic from the dashboard, or invoking it from terminal throws an instance of 'std::out_of_range' exception. The package has worked correctly before, so this is a new problem. Of course, as soon as the exception is thrown, the window that might have been up for a quarter of a second bombs out.