In blog.inc and possibly user.inc, there is a failure in mysite_type_blog_block_node when the UID of the post is 0 (which is allowed in some cases).
Passing the 0 id to mysite_type_hook_title causes the error. User 0 cases must be accounted for.
Comments
Comment #1
agentrickardmysite_type_user_title handles this correctly. Apply to blog.inc.
Comment #2
agentrickardThere were two bugs uncovered here. One is missing title.
The other is that the block handler assumed $type_id > 0, which is not always the case.
This has been fixed and needs to be committed.
Comment #3
(not verified) commented