This was all in a LiveCD session; evidently the LiveCD uses itself as a source, or at least lists itself.
Using the same CD in the same computer, I've now got Add/Remove & Synaptic working, at least for this session.
This might have been one of those "computers being stupid" things - I'm going to use the same CD tomorrow on a friend's machine, so we'll see what it does then.
This was all in a LiveCD session; evidently the LiveCD uses itself as a source, or at least lists itself.
Using the same CD in the same computer, I've now got Add/Remove & Synaptic working, at least for this session.
This might have been one of those "computers being stupid" things - I'm going to use the same CD tomorrow on a friend's machine, so we'll see what it does then.