Hmm first up a little more information about your set up would be good.
Are you running single or multisite WordPress?
Are you on the latest WordPress?
Have you checked the minimal server requirements for WordPress and that your server meets these?
Do you have a memory limit in your php.ini file (you may have to ask your host about this)?
Have you tried deactivating all other plugins then just trying BuddyPress with the default theme?
No need to link to your admin panel – make sure you don’t put private information also (just incase) on this forum as it’s a public forum.
1) Single
2) 3.2.1
3) CPU: 2x QuadCore Xeon 2.5Ghz
RAM: 12GB
HDD: 4x300GB SATA2 10k v RAID10
4) I dont know 
5) No
If you can try 5 and find out 4 we may have some more information to judge with.
I tried turn off all plugins and BP works. Thanks
Ok so it’s probably a plugin that isn’t updated and as a result being an issue – that’s my best guess here.
I might actually be able to help out with this one. I was getting the same errors. Apparently this is because your wp-config.php is reading the default memory allocation of about 8meg that your host usually sets up by default. Once I edit my wp-config file to allocate 64 or 96 meg with the below instructions it popped back up fine.
https://codex.wordpress.org/Editing_wp-config.php#Increasing_memory_allocated_to_PHP
