Hi Rene,
To trouble shoot this I would try running the 2.2.1.5 script manually.
Its located at /Setup/applications/mojoportal-core/SchemaUpgradeScripts/pgsql/2.2.1.5.config
Maybe running it manually will give better clues.
If it runs then you need to do an insert in the mp_schemaversion table.
insert into mp_schemaversion (applicationid,applicationname,major,minor,build,revision)
values ('077e4857-f583-488e-836e-34a4b04be855','mojoportal-core',2,2,1,5);
after that you can try the /Setup/Default.aspx page again and see if it will run the rest. If you have to run more manually just increment the version in this tables according to the script you ran.
Hope it helps,
Joe