I'm facing the same issue.
No matter what configuration I'm trying to change, the default one comes up again.
Please can you tell me how to resolve this issue?
I have set permission of 'data' folder to 0777.
Tried deleting "generator/data/generator.conf" but in vain.
That files comes up again with default settings.
Also my sitemap.xml always remains empty. Can this issue be the problem?