I'm sorry but what you are telling me makes no sense at all.
If you were upgrading from 2.3.5.4 it would already have 2.3.5.4 for mojoportal-core in the mp_SchemaVersion table
This is why I suspect you have been leaving out information or giving me false answer to the questions I've asked you. You are either not correctly restoring the database or doing something to make the database in a strange state that makes these errors happen when trying to upgrade.
If the site was really at version 2.3.5.4 and the database user is dbo and the tables and procedures all have the dbo prefix, then the mp_SchemaVersion table would already have mojoportal-core as version 2.3.5.4 and the setup page would start upgrading with script version 2.3.5.6 not with script 2.2.1.9
If you site was really at version 2.2.1.8 then it would still need to run the same upgrade scripts to upgrade to version 2.3.5.4.
you should not manually change the version in the database unless you manually are able to run the script from query analyzer with no errors, if you run the script manually then you must update the version of mojoportal-core in mp_SchemaVersion to match the script version
You are either leaving out information about what you did to the database (ie if you restored it how you restored it) or you are not giving truthfull answers to the questions I asked you in trying to figure out what is wrong in your database. I cannot help to solve the problem without complete and accurate information.
You also have not mentioned what version of SQL Server you are using. At minimum it must be SQL 2005 with all the service paks installed or higher.