Re: White Screen of Death (Please Help :( )
If WPMU + BuddyPress is working fine–that is when you just have BuddyPress installed and activated and no other plugins activated–then this issue is best solved by posting on the WPMU forums.
As a general rule, though, if you suspect that the issue is plugin related, then you should follow the recommended procedure for tracking down misbehaving plugins. You deactivate all plugins and then reactivate plugins one at a time, each time testing out WPMU to see if it is working. If so, you reactivate the next plugin and so on until you find the plugin that seems to be causing the issue.
Also, make sure that you are using the most recent plugin for the version of WPMU you’re running. If a plugin is not yet updated to run in the version of WPMU you’ve installed, then that could be an issue. Contact the plugin developer and ask when they plan to update it.
You also need to check your serve’s log files to see if there are any errors that could help in figuring out the issue. If you don’t know how to do that, your hosting firm can help.
But please search the WPMU forums first and then post there if you cannot find an answer. This sounds like a plugin conflict and has nothing to do with BuddyPress.