Hi,
That error also isn't coming from mojoPortal but seems to be an error in web site panel.
How did you install mojoPortal?
If the files have been deployed and the database exists it should be just a matter of specifying the database connection string if it isn't already specified.
Typically the user.config.sample file in the root would be renamed to user.config and the database conneciton string in that file would need to be set if it isn't already with the db name user password etc.
Once that is done just visit the siteroot/Setup/Default.aspx page so mojoPortal can run its database scripts and setup routine, where siteroot is your domain name.
Hope that helps,
Joe