@delphin. Ok, I have looked at this issue. What happens, it seems, is that the update SQL was not installed properly for some reason at the first installation/update, and thus certain things are missing.
You can manually fix it by accessing 1.5.0.sql in the backend/sql/updates folder, and copy/paste/execute the SQL statements in that file direction into your phpMyAdmin console. This will fix it manually.
If you want to wait I bit, I am going to release version 1.5.1 some time today to address this issue. So, all you will need to do is to upgrade to the minor release version 1.5.1.