Looking in Google Webmaster Tools, I noticed it said there were errors with my sitemap for Potluck.com ( http://potluck.com/sitemap.xml ) -- Google's details showed a Parsing Error on line 5026.
I looked at the sitemap, and it appears blank in my browser, though looking at source code, all seems basically fine.
I tried to rebuild the sitemap manually within the Dashboard. No change.
Since I am running WP 2.1.2 on this particular site and was using sitemaps plugin 3.0b6, I thought to look for a plugin update. I noticed that 3.1.0.1 was available for all WP 2.1 or higher, so I updated. Still no change.
When I rebuild the sitemap manually in the Dashboard now, I get a fatal error indicating "Call to undefined function: user_trailingslashit()" in sitemap-core.php on line 1963
When I use debug mode, I get a different fatal error: "Unknown function: wp_load_alloptions()" in sitemap-ui.php on line 108
Any help would be appreciated.