Kimmo Kivelä, you can not simple copy the 1.7.3 database for 1.7.4 software version. You will need to run the queries from the ow_updates/update.php file in order to create tables and columns which did not exist in 1.7.3 version.
It would be better to go through update process properly. Please elaborate what the issues you faced during the update process. Did you create a backup before starting update process?
Uh. I messed up my Installatron install. I cannot update it via installatron any more, and when I try to update it as standard method /ow_updates/, I get page like:
Index of /ow/ow_updates