when activating and other plugins are already installed the fatal error shows up. ok so disable all the others (after testing the plugin for network install so hey it shoudl work right?) activate. now activate the others, web site 'broken' have to remove the bbpress.
Having proper error routines would IMHO help reduce this annoyance. this way the errors coudl be 'caught' and big tracked back to Wp community in the same way that Mozilla /Linux does.