Hi Marco,
Then how did it work before since all the scripts have dbo, you user must have been dbo at one time or it would not have worked before.
I just emailed you a file to replace a few of the upgrade scripts. Please replace the files as indicated and then try the setup page again.
If that does not solve it, we do have a way to handle it if your user is not dbo but it seems strange to have to solve it for an exsiting site and the solution could break things if some of your existing tables are named with dbo. So this solution is really for new installations and it is very risky to change it for upgrades and may cause more problems.
You "could" change this setting in Web.config from:
<add key="MSSQLOwnerPrefix" value="[dbo]."/>
to
<add key="MSSQLOwnerPrefix" value="[yourdbuser]."/>
then it will replace dbo in the scripts with your db user name before it executes the script. But again this is very risky for an upgrade, it is only meant for new instalaltions where dbo is not allowed, I would backup the database first in case it doesn't work.
most hosts do allow dbo since dbo is only for the specific database not for the whole server, it just gives your user complete control over his own database.
Hope that helps,
Joe