bbPress.org

Oh, that is strange, can you check the contents of the following file for me on your beta 2:

bbpress/includes/admin/converter.php#L653

That line should read $max_index_length = 191;

One other thing, you might need to run the “reset forums” tool first from:

/wp-admin/tools.php?page=bbp-reset

That will delete that old table (and *all* your forum data) and make it available to be created in the updated format.