White screen when a new theme selected (BuddyPress)

I'm having a problem when a new theme is selected.

I just get a white screen in the admin area. This only happens when I have BuddyPress selected. I deactivated it and everything worked fine.

If I removed all the themes from the themes folder, it would work fine if I selected the BuddyPress default theme.

WP: 3
BP: 1.2.5.2