Reply To: Upgrade from 1.2.8 to 1.8.1 ISSUE
When you do anything like upgrading an app and you’re not 100% familiar with the process you MUST read the documentation, looking for any guides or instructions to follow.
You are attempting to update a really outdated version of BP, and you cannot do a straight jump to the latest stable:
Read this page and link to upgrade process for 1.2 versions to 1.5
https://codex.buddypress.org/getting-started/upgrading-buddypress/
And strong word of advice, keep current with latest releases of BP in the intervening version releases there have been a few critical security fixes that left un-patched leave your site and others vulnerable
