Config file is not writable

[bh1]

permissions on it are 777 for now.
fails
Why does it have to write to the config file when starting a manual crawl?
If re-set back to 644 like you mention then how is CRON going to run/write to it?

[XML-Sitemaps Support]

It's only required to have 0666 permissions for config.inc.php file when you modify configuration. You can revert it to 0644 after that, it's not required to RUN sitemap generator.