If the forum was changed from non-wiki to wiki, existing threads will not have article metadata created, making it impossible to set them as chapters of a book, among other things.
Fixed in the current ZIP.
In
vault/special_plugins_data.php, find:
Code:
!$vbulletin->forumcache[$data->fetch_field('forumid')]['vault_type']
Replace with:
Then, you will need to turn wiki in that forum to "Disabled", save, then change it back to "wiki".
Warning: this will clear any article revision history and any chapters in that particular forum. You will need to add the chapters again. This is not a bug. VaultWiki erases data that it believes will no longer be needed (since a thread is not an article anymore, there is no use for revisions, etc).