Very strange. Can you check your file permissions, to make sure that the web server can read the contents of bp-core?
Heres what I did:
(this is on a multisite – yes my host allows for e to execute php files and -press type programs, including wordpress and bbpress)
I deleted my old BPress for other issues that worked upon its deletion. I then searched and installed this version through the dashboard for network admin and then tried to network activate. the first tie I got that error, I then checked the permissions and tried an experiment by setting things from 750 – 777 for all files and directories (including sub directories) of my “upload to” folder. so this made all associated files with bp 777. I tried activating it again….same issue.
Any ideas? Testing a theory that the plugin installer in the WP dashboard did not set up or download, or extract all the bp files properly, deleting the plugin from ftp took 1 second where as it usually takes a minute.
fixed it: It looks like the WP Plugin installer did not do its job properly
I had a problem upgrading in test install with 4 dozen WP/BP/MU plugins being checked out. It turns out that not all the BuddyPress files were uploaded in auto upgrade from dashboard. Most probably plugin conflict. Suggest re-upload BuddyPress manually via FTP/cpanel – it worked for me.