I have cleared the swamps and I'm supposed to talk to the Old Woman in the cabin to the south of the Lizardmen. Trouble is, when I go there I get no response. The message is: "There is no response from inside the cabin" or something similar.

Why won't the old woman show up? Is this a known bug?

Give me a bit more information. Have you already been to Lowangen? Are you just exploring or did you get there to do the quest?

I have retrieved the Salamander Stone from the Dwarven Pit and taken it to Lowangen. Then I received a quest from Master Eolen in Lowangen to look for a soldier who may have gone to the swamps, so that's where I headed next. After doing some reading, you're supposed to be able to talk to the old woman after accepting Eolen's quest and helping the Lizardmen. I have done both, so I'm not sure what I am missing.

I fear that the quest might be broken somehow and I have to reload from an older save.

I did kill the engulfer for the Lizardmen and then they told me that the Old Woman lived to the south and liked her privacy. I went to her house directly afterwards and she isn't there. Maybe I acidentally killed the swamp rantzy that is part of the quest and just forgot about it. If that's the case then I would expect the quest to be broken and I'll just have to reload.

This swamp is tough. I must have missed something in Lowangen because I could not afford what low-end armor that was available there. So I left Lowangen with pretty much no armor and these battles are brutal! To have to clear the swamp again in this condition, LOL.

Edit: I ended up loading a save back when I was still in Lowangen, stole and cheated my way to roughly 300 ducats and bought some armor from Dragan's associate. Now I'm back in the swamp starting fresh, this time with some better equipment. It's still amazing how hard those stinking swamp rantzies can hit even when my warrior has AC 9.