The search index could not be updated. The site is misconfigured. Contact an administrator. SQLSTATE[42000]: Syntax error or access violation: 1064 unknown table 'tiki_main_67e2559f7089d' in delete request
The forum posts are stored in the tiki_comments table. Forum posts will contain the value "forum" in the objectType column.
I don't think a trigger on tiki_comments would mess up Tiki.