WP MU 3.2.1 and BuddyPress 1.2.9 : Blog in sub domain don't reach activity, memebers, group pa

Hi,

My config :

WordPress 3.2.1 MU
BuddyPress 1.2.9
Dedicated server

WP MU is installed with sub domains option.

WP MU files are stored in /var/www/ff-mu/wordpress
BuddyPress is installed on /var/www/ff-mu/wordpress/wp-content/plugins/buddypress

Site root : fansfoot.com Theme : BuddyPress Default
Blog : blog.fansfoot.com Theme : BuddyPress Default

1st question :
Is it possible to have 2 communities in WP MU + BuddyPress with sub domains option actived (I know it's possible with sub-folders option, but worst for SEO point of view). I mean, one for fansfoot.com and for blog.fansfoot ?

2nd question

fansfoot.com is working well activity, members, groups menus have good links and show good pages.

Blog.fansfoot.com is working bad activity, members, groups menus have good links and show BADpages.

Look at error message below.

Please advice