Thanks for your reply

OK, I performed the following steps:
1) Uninstall KonaKart
2) Delete all KonaKart's folders and files from Program Files
3) Create new MySQL database
4) Install KonaKart one more time from *.exe file (Installation processed sucessfuly)
Front Office of the KonaKart shop is running correctly, but the KonaKart Back Office (konakartadmin) is failed.
Screenshot below presents my situation: