Well thats some progress and leads me to believe ithe last error was ByteFX related, but the 0 in that path means it thinks the SiteID is 0 which makes me think its missing data in the mp_Sites or mp_Pages table. Make sure there are rows in both and the siteID in the rows is 1.
This is the same error a user had yesterday, look at the thread about upgrade error in this forum and see the page insert statements that fixed it for him.