I'm not sure how it happened, but you seem to have ended up with two blogs assigned to the same user in the same portal.  Theoretically this should never happen in the current version of the blog module (03.04).  If it were me, I would clean this up at the database level.  You can view the list of offending blogs by entering the following Query into the SQL page under the Host tab:

[Edited to account for child blogs]

--- Begin SQL ---

SELECT PortalId, UserId INTO #TempBlogs
FROM {databaseOwner}{objectQualifier}Blog_Blogs
WHERE ParentBlogId = -1
GROUP BY PortalId, UserId
HAVING Count(*) > 1

SELECT b.Title, u.UserName FROM {databaseOwner}{objectQualifier}Blog_Blogs b
 JOIN #TempBlogs tb ON tb.PortalId = b.PortalId AND tb.UserId = b.UserId
 JOIN {databaseOwner}{objectQualifier}Users u ON b.UserId = u.UserId

--- End SQL ---

If this query produces results, then my next step would be to perform a backup of the database (just for sanity sake) and then a delete of the offending record from the Blog_Blogs table.

HTH,

Don

I updated my original query to ignore child blogs.