Do you mean hosted blogs aren’t working? Were they working before installing BuddyPress?
i don’t know (maybe not) … it would be great if someone could have a look at it, please email me at gugus (at) idotter (dot) ch
Did you by any chance copied/replaced this install from another place? If you did, maybe you haven’t updated your wp-config and some other files.
Only other option beside that I can think of is that your server/host doesnt support mod_rewrite..
Both unlikely since your admin area does work. Try disabling buddypress and see if your normal wpmu pages work..
Also try updating your permalink structure.
i updated PL-structure, i reinstalled wp mu and buddypress … but neither bp nor wpmu works properly. mod_rewrite is activated 
there seems to be a problem by the URIs. I opened a new blog, but when i want to visit it or jump into its backend, it can’t find the location blog.idotter.ch/wpmu/wp-admin
Have you tried disabling BuddyPress – dies the problem still occur?
ahh I see your problem ,while i checked your site.
1.You have wordpress mu installed in a subdirectory wpmu
2.But you have installed wordpress mu to use subdomain style address ,which will not work.
Workaround
1.Install wordpress mu in wpmu(subdirectory as it is now) but at the time of installation select “Sub- directories” and go ahead, your wpmu will work correctly and you will have blogs with address as
idotter.ch/wpmu/blog_address
Or
2.Install wpmu in the root domain with subdomain style,enable wildcard subdomain and you will have blogs like blog.yoursite.com working.
Hope it helps.
thx, it seems to work now … i’ll test with bp …
