So... I've got some info, but not as much, as I expected.
I have a xf_post table dump, but it is a bit old, so there weren't some posts...
And currently, admin of that web has deleted / moved some posts from that list (IDs I've got form the ACP server error list, text of the error is in the attachment), so it's not possible to find out what was wrong with deleted posts...
So, attached you will find error text and csv files with selection from the dumped table (from backup) and from the current table.
Csv files were made with the next query
[CODE]SELECT post_id, post_date, message_state, position FROM xf_post WHERE post_id IN (
21678, 21698, 21702, 21705, 21711, 21754, 21774, 21872, 21908, 22005, 22007, 22010, 22038, 22147, 22162, 22187, 22192, 22458, 26123, 26274, 26746, 26786, 26787, 26795, 26797, 26800, 26801, 26807, 26808, 26813, 26816, 26822, 26825
)[/CODE]