Oh yeah I remember I did change it to use SubSonic to test for the mp_Sites table not long ago but I think that is the only place where the MS SQL version is using SubSonic. I did that because the syntax for checking the schema is changing over versions of MS SQL so I figured those differences could be abstracted behind SubSonic.
I don't know anything about db_backup folder thats not something mojoportal code is doing. It doesn't create database backups.
Without seeing the error messages it not possible for me to diagnose what is happening.
I know a number of people have posted problems with installation at Go Daddy, if you search this site for "go daddy" you will see a number of results.
I think some of them did succeed in the end.