marjancz , your player would be using the v9.0.xx series firmwares. i'll suggest trying all the v9.0.xx firmwares in the downloads section here
http://www.mympxplayer.org/actions-9...mare-dc37.html
However, it is not possible to tell which firmware will work with your player, so try all those for your screen size.
If they do not work, try contacting your seller if they have the firmware to send to you. Also check the CD that came with your player, sometimes it is inside and should be in .bin or .fw format.