Yes there is a known problem that happens sometimes with the 126.96.36.199 upgrade script of the blog. It is migrating comments fromt eh older blog comment system into the newer one but the newer one has only 50 chars allowed for the name and the old one had 100 so if there was data in the old one that is larger than 50 chars it throws this error.
If you edit the file at
look for the select statement after insert statement,
change to Substring(bc.[Name],0,50),
Then visit the setup page again so it can run that script as well as other newer ones.
I will add this same change into my copy of the script to prevent this in the future.
Hope that helps,