Re: Another problem with blogs
Some of the widgets like the ‘activity’ and ‘recent posts’ widgets were designed to run on blog id 1 only. If you are comfortable changing the code in the bp core then here’s the spots:
Activity widget: /mu-plugins/bp-activity/bp-activity-widgets.php. Line #8 and line #30 have checks for blog id > 1. Modify to reflect your site.
Recent Posts widget: /mu-plugins/bp-blogs/bp-blogs-widgets.php. Line #8 and line #30 have checks for blog id > 1. Modify to reflect your site.
Welcome and Members widget: /mu-plugins/bp-core/bp-core-widgets.php. Line #8 checks for blog id > 1. Modify to reflect your site.
Groups widget: /mu-plugins/bp-groups/bp-groups-widgets.php. Line #8 checks for blog id > 1. Modify to reflect your site.
CAUTION: Your site may melt down. Your friends may leave you. Your pets may not like you anymore. I’ve heard of people’s cars not starting after making changes to the bp core. 
