XML Sitemap components cause PHP errors in Modules page

XML Sitemap creates the following error, 4 times:

warning: Invalid argument supplied for foreach() in /home/content/e/r/r/errorad/html/drupal6rc2/modules/system/system.admin.inc on line 580.

This looks like it corresponds to the 4 sub-components of XML Sitemap: Engines, Nodes, Terms, and Users.

Type php
Date Friday, January 11, 2008 - 16:40
User Shadyman
Location http://erroraccessdenied.com/drupal6rc2/admin/build/modules
Referrer http://erroraccessdenied.com/drupal6rc2/?q=admin
Message Invalid argument supplied for foreach() in /home/content/e/r/r/errorad/html/drupal6rc2/modules/system/system.admin.inc on line 580.
Severity error