Hi @martin,
This error:
DB Error: Incorrect string value: '\xD0\x9D\xD0\xBE\xD0\xB2...' for column 'subject' at row 1
…is related to your character set configuration. When you create your database, make sure you set its default character set to UTF8. Also ensure that the options you choose on the installation form correspond with UTF8.
Regards,
Alec Smecher
Public Knowledge Project Team